* Kernel build fail with 'btf_encoder__encode: btf__dedup failed!'
@ 2023-01-22 17:48 Daniel Xu
2023-01-22 21:25 ` Daniel Xu
2023-01-23 8:06 ` Jiri Olsa
0 siblings, 2 replies; 29+ messages in thread
From: Daniel Xu @ 2023-01-22 17:48 UTC (permalink / raw)
To: bpf@vger.kernel.org; +Cc: Arnaldo Carvalho de Melo
Hi,
I'm getting the following error during build:
$ ./tools/testing/selftests/bpf/vmtest.sh -j30
[...]
BTF .btf.vmlinux.bin.o
btf_encoder__encode: btf__dedup failed!
Failed to encode BTF
LD .tmp_vmlinux.kallsyms1
NM .tmp_vmlinux.kallsyms1.syms
KSYMS .tmp_vmlinux.kallsyms1.S
AS .tmp_vmlinux.kallsyms1.S
LD .tmp_vmlinux.kallsyms2
NM .tmp_vmlinux.kallsyms2.syms
KSYMS .tmp_vmlinux.kallsyms2.S
AS .tmp_vmlinux.kallsyms2.S
LD .tmp_vmlinux.kallsyms3
NM .tmp_vmlinux.kallsyms3.syms
KSYMS .tmp_vmlinux.kallsyms3.S
AS .tmp_vmlinux.kallsyms3.S
LD vmlinux
BTFIDS vmlinux
FAILED: load BTF from vmlinux: No such file or directory
make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255
make[1]: *** Deleting file 'vmlinux'
make: *** [Makefile:1264: vmlinux] Error 2
This happens on both bpf-next/master (84150795a49) and 6.2-rc5
(2241ab53cb).
I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as
upstream pahole on master (02d67c5176) and upstream pahole on
next (2ca56f4c6f659).
Of the above 6 combinations, I think I've tried all of them (maybe
missing 1 or 2).
Looks like GCC got updated recently on my machine, so perhaps
it's related?
CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111"
I'll try some debugging, but just wanted to report it first.
Thanks,
Daniel
^ permalink raw reply [flat|nested] 29+ messages in thread* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-22 17:48 Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' Daniel Xu @ 2023-01-22 21:25 ` Daniel Xu 2023-01-23 8:06 ` Jiri Olsa 1 sibling, 0 replies; 29+ messages in thread From: Daniel Xu @ 2023-01-22 21:25 UTC (permalink / raw) To: bpf@vger.kernel.org; +Cc: Arnaldo Carvalho de Melo On Sun, Jan 22, 2023, at 10:48 AM, Daniel Xu wrote: > Hi, > > I'm getting the following error during build: > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 > [...] > BTF .btf.vmlinux.bin.o > btf_encoder__encode: btf__dedup failed! > Failed to encode BTF > LD .tmp_vmlinux.kallsyms1 > NM .tmp_vmlinux.kallsyms1.syms > KSYMS .tmp_vmlinux.kallsyms1.S > AS .tmp_vmlinux.kallsyms1.S > LD .tmp_vmlinux.kallsyms2 > NM .tmp_vmlinux.kallsyms2.syms > KSYMS .tmp_vmlinux.kallsyms2.S > AS .tmp_vmlinux.kallsyms2.S > LD .tmp_vmlinux.kallsyms3 > NM .tmp_vmlinux.kallsyms3.syms > KSYMS .tmp_vmlinux.kallsyms3.S > AS .tmp_vmlinux.kallsyms3.S > LD vmlinux > BTFIDS vmlinux > FAILED: load BTF from vmlinux: No such file or directory > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > make[1]: *** Deleting file 'vmlinux' > make: *** [Makefile:1264: vmlinux] Error 2 > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 > (2241ab53cb). > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as > upstream pahole on master (02d67c5176) and upstream pahole on > next (2ca56f4c6f659). > > Of the above 6 combinations, I think I've tried all of them (maybe > missing 1 or 2). > > Looks like GCC got updated recently on my machine, so perhaps > it's related? > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" > > I'll try some debugging, but just wanted to report it first. > > Thanks, > Daniel Applying the following diff: diff --git a/src/btf.c b/src/btf.c index ae1520f..8a2fa36 100644 --- a/src/btf.c +++ b/src/btf.c @@ -4576,8 +4576,11 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) int ref_type_id; long h; - if (d->map[type_id] == BTF_IN_PROGRESS_ID) + if (d->map[type_id] == BTF_IN_PROGRESS_ID) { + struct btf_type *t = btf_type_by_id(d->btf, type_id); + pr_warn("eloop type_id=%d, kind=%d, type=%d\n", type_id, btf_kind(t), t->type); return -ELOOP; + } if (d->map[type_id] <= BTF_MAX_NR_TYPES) return resolve_type_id(d, type_id); Yields: BTF .btf.vmlinux.bin.o libbpf: eloop type_id=2, kind=10, type=2 btf_encoder__encode: btf__dedup failed! Failed to encode BTF So it's a CONST pointing to itself? I'm somewhat out of ideas here. ^ permalink raw reply related [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-22 17:48 Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' Daniel Xu 2023-01-22 21:25 ` Daniel Xu @ 2023-01-23 8:06 ` Jiri Olsa 2023-01-24 6:13 ` Daniel Xu 1 sibling, 1 reply; 29+ messages in thread From: Jiri Olsa @ 2023-01-23 8:06 UTC (permalink / raw) To: Daniel Xu; +Cc: bpf@vger.kernel.org, Arnaldo Carvalho de Melo On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: > Hi, > > I'm getting the following error during build: > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 > [...] > BTF .btf.vmlinux.bin.o > btf_encoder__encode: btf__dedup failed! > Failed to encode BTF > LD .tmp_vmlinux.kallsyms1 > NM .tmp_vmlinux.kallsyms1.syms > KSYMS .tmp_vmlinux.kallsyms1.S > AS .tmp_vmlinux.kallsyms1.S > LD .tmp_vmlinux.kallsyms2 > NM .tmp_vmlinux.kallsyms2.syms > KSYMS .tmp_vmlinux.kallsyms2.S > AS .tmp_vmlinux.kallsyms2.S > LD .tmp_vmlinux.kallsyms3 > NM .tmp_vmlinux.kallsyms3.syms > KSYMS .tmp_vmlinux.kallsyms3.S > AS .tmp_vmlinux.kallsyms3.S > LD vmlinux > BTFIDS vmlinux > FAILED: load BTF from vmlinux: No such file or directory > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > make[1]: *** Deleting file 'vmlinux' > make: *** [Makefile:1264: vmlinux] Error 2 > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 > (2241ab53cb). > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as > upstream pahole on master (02d67c5176) and upstream pahole on > next (2ca56f4c6f659). > > Of the above 6 combinations, I think I've tried all of them (maybe > missing 1 or 2). > > Looks like GCC got updated recently on my machine, so perhaps > it's related? > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" > > I'll try some debugging, but just wanted to report it first. hi, I can't reproduce that.. can you reproduce it outside vmtest.sh? there will be lot of output with patch below, but could contain some more error output jirka --- diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 32e573943cf0..05ac3ced89e7 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -125,7 +125,7 @@ gen_btf() vmlinux_link ${1} info "BTF" ${2} - LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} + LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -V -J ${PAHOLE_FLAGS} ${1} # Create ${2} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all ^ permalink raw reply related [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-23 8:06 ` Jiri Olsa @ 2023-01-24 6:13 ` Daniel Xu 2023-01-27 22:28 ` Alexandre Peixoto Ferreira 0 siblings, 1 reply; 29+ messages in thread From: Daniel Xu @ 2023-01-24 6:13 UTC (permalink / raw) To: Jiri Olsa; +Cc: bpf@vger.kernel.org, Arnaldo Carvalho de Melo Hi Jiri, On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >> Hi, >> >> I'm getting the following error during build: >> >> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >> [...] >> BTF .btf.vmlinux.bin.o >> btf_encoder__encode: btf__dedup failed! >> Failed to encode BTF >> LD .tmp_vmlinux.kallsyms1 >> NM .tmp_vmlinux.kallsyms1.syms >> KSYMS .tmp_vmlinux.kallsyms1.S >> AS .tmp_vmlinux.kallsyms1.S >> LD .tmp_vmlinux.kallsyms2 >> NM .tmp_vmlinux.kallsyms2.syms >> KSYMS .tmp_vmlinux.kallsyms2.S >> AS .tmp_vmlinux.kallsyms2.S >> LD .tmp_vmlinux.kallsyms3 >> NM .tmp_vmlinux.kallsyms3.syms >> KSYMS .tmp_vmlinux.kallsyms3.S >> AS .tmp_vmlinux.kallsyms3.S >> LD vmlinux >> BTFIDS vmlinux >> FAILED: load BTF from vmlinux: No such file or directory >> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >> make[1]: *** Deleting file 'vmlinux' >> make: *** [Makefile:1264: vmlinux] Error 2 >> >> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >> (2241ab53cb). >> >> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >> upstream pahole on master (02d67c5176) and upstream pahole on >> next (2ca56f4c6f659). >> >> Of the above 6 combinations, I think I've tried all of them (maybe >> missing 1 or 2). >> >> Looks like GCC got updated recently on my machine, so perhaps >> it's related? >> >> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >> >> I'll try some debugging, but just wanted to report it first. > > hi, > I can't reproduce that.. can you reproduce it outside vmtest.sh? > > there will be lot of output with patch below, but could contain > some more error output Thanks for the hints. Doing a regular build outside of vmtest.sh seems to work ok. So maybe it's a difference in the build config. I'll put a little more time into debugging to see if it goes anywhere. But I'll have to get back to the regularly scheduled programming soon. [...] Thanks, Daniel ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-24 6:13 ` Daniel Xu @ 2023-01-27 22:28 ` Alexandre Peixoto Ferreira 2023-01-28 0:00 ` Jiri Olsa 0 siblings, 1 reply; 29+ messages in thread From: Alexandre Peixoto Ferreira @ 2023-01-27 22:28 UTC (permalink / raw) To: Daniel Xu, Jiri Olsa; +Cc: bpf@vger.kernel.org, Arnaldo Carvalho de Melo On 1/24/23 00:13, Daniel Xu wrote: > Hi Jiri, > > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >> On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>> Hi, >>> >>> I'm getting the following error during build: >>> >>> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>> [...] >>> BTF .btf.vmlinux.bin.o >>> btf_encoder__encode: btf__dedup failed! >>> Failed to encode BTF >>> LD .tmp_vmlinux.kallsyms1 >>> NM .tmp_vmlinux.kallsyms1.syms >>> KSYMS .tmp_vmlinux.kallsyms1.S >>> AS .tmp_vmlinux.kallsyms1.S >>> LD .tmp_vmlinux.kallsyms2 >>> NM .tmp_vmlinux.kallsyms2.syms >>> KSYMS .tmp_vmlinux.kallsyms2.S >>> AS .tmp_vmlinux.kallsyms2.S >>> LD .tmp_vmlinux.kallsyms3 >>> NM .tmp_vmlinux.kallsyms3.syms >>> KSYMS .tmp_vmlinux.kallsyms3.S >>> AS .tmp_vmlinux.kallsyms3.S >>> LD vmlinux >>> BTFIDS vmlinux >>> FAILED: load BTF from vmlinux: No such file or directory >>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>> make[1]: *** Deleting file 'vmlinux' >>> make: *** [Makefile:1264: vmlinux] Error 2 >>> >>> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>> (2241ab53cb). >>> >>> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>> upstream pahole on master (02d67c5176) and upstream pahole on >>> next (2ca56f4c6f659). >>> >>> Of the above 6 combinations, I think I've tried all of them (maybe >>> missing 1 or 2). >>> >>> Looks like GCC got updated recently on my machine, so perhaps >>> it's related? >>> >>> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>> >>> I'll try some debugging, but just wanted to report it first. >> hi, >> I can't reproduce that.. can you reproduce it outside vmtest.sh? >> >> there will be lot of output with patch below, but could contain >> some more error output > Thanks for the hints. Doing a regular build outside of vmtest.sh > seems to work ok. So maybe it's a difference in the build config. > > I'll put a little more time into debugging to see if it goes anywhere. > But I'll have to get back to the regularly scheduled programming > soon. 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails in pahole when CONFIG_X86_KERNEL_IBT is set. Thanks, -- Alexandre Peixoto Ferreira ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-27 22:28 ` Alexandre Peixoto Ferreira @ 2023-01-28 0:00 ` Jiri Olsa 2023-01-28 0:21 ` Daniel Xu 2023-01-28 19:23 ` Alexandre Peixoto Ferreira 0 siblings, 2 replies; 29+ messages in thread From: Jiri Olsa @ 2023-01-28 0:00 UTC (permalink / raw) To: Alexandre Peixoto Ferreira Cc: Daniel Xu, Jiri Olsa, bpf@vger.kernel.org, Arnaldo Carvalho de Melo On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: > > > On 1/24/23 00:13, Daniel Xu wrote: > > Hi Jiri, > > > > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: > > > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: > > > > Hi, > > > > > > > > I'm getting the following error during build: > > > > > > > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 > > > > [...] > > > > BTF .btf.vmlinux.bin.o > > > > btf_encoder__encode: btf__dedup failed! > > > > Failed to encode BTF > > > > LD .tmp_vmlinux.kallsyms1 > > > > NM .tmp_vmlinux.kallsyms1.syms > > > > KSYMS .tmp_vmlinux.kallsyms1.S > > > > AS .tmp_vmlinux.kallsyms1.S > > > > LD .tmp_vmlinux.kallsyms2 > > > > NM .tmp_vmlinux.kallsyms2.syms > > > > KSYMS .tmp_vmlinux.kallsyms2.S > > > > AS .tmp_vmlinux.kallsyms2.S > > > > LD .tmp_vmlinux.kallsyms3 > > > > NM .tmp_vmlinux.kallsyms3.syms > > > > KSYMS .tmp_vmlinux.kallsyms3.S > > > > AS .tmp_vmlinux.kallsyms3.S > > > > LD vmlinux > > > > BTFIDS vmlinux > > > > FAILED: load BTF from vmlinux: No such file or directory > > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > > > make[1]: *** Deleting file 'vmlinux' > > > > make: *** [Makefile:1264: vmlinux] Error 2 > > > > > > > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 > > > > (2241ab53cb). > > > > > > > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as > > > > upstream pahole on master (02d67c5176) and upstream pahole on > > > > next (2ca56f4c6f659). > > > > > > > > Of the above 6 combinations, I think I've tried all of them (maybe > > > > missing 1 or 2). > > > > > > > > Looks like GCC got updated recently on my machine, so perhaps > > > > it's related? > > > > > > > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" > > > > > > > > I'll try some debugging, but just wanted to report it first. > > > hi, > > > I can't reproduce that.. can you reproduce it outside vmtest.sh? > > > > > > there will be lot of output with patch below, but could contain > > > some more error output > > Thanks for the hints. Doing a regular build outside of vmtest.sh > > seems to work ok. So maybe it's a difference in the build config. > > > > I'll put a little more time into debugging to see if it goes anywhere. > > But I'll have to get back to the regularly scheduled programming > > soon. > 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails > in pahole when CONFIG_X86_KERNEL_IBT is set. could you plese attach your config and the build error? I can't reproduce that thanks, jirka ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-28 0:00 ` Jiri Olsa @ 2023-01-28 0:21 ` Daniel Xu 2023-01-28 0:23 ` Daniel Xu 2023-01-28 19:23 ` Alexandre Peixoto Ferreira 1 sibling, 1 reply; 29+ messages in thread From: Daniel Xu @ 2023-01-28 0:21 UTC (permalink / raw) To: Jiri Olsa, Alexandre Peixoto Ferreira Cc: bpf@vger.kernel.org, Arnaldo Carvalho de Melo Hi Jiri & Alexandre, On Fri, Jan 27, 2023, at 5:00 PM, Jiri Olsa wrote: > On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >> >> >> On 1/24/23 00:13, Daniel Xu wrote: >> > Hi Jiri, >> > >> > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >> > > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >> > > > Hi, >> > > > >> > > > I'm getting the following error during build: >> > > > >> > > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >> > > > [...] >> > > > BTF .btf.vmlinux.bin.o >> > > > btf_encoder__encode: btf__dedup failed! >> > > > Failed to encode BTF >> > > > LD .tmp_vmlinux.kallsyms1 >> > > > NM .tmp_vmlinux.kallsyms1.syms >> > > > KSYMS .tmp_vmlinux.kallsyms1.S >> > > > AS .tmp_vmlinux.kallsyms1.S >> > > > LD .tmp_vmlinux.kallsyms2 >> > > > NM .tmp_vmlinux.kallsyms2.syms >> > > > KSYMS .tmp_vmlinux.kallsyms2.S >> > > > AS .tmp_vmlinux.kallsyms2.S >> > > > LD .tmp_vmlinux.kallsyms3 >> > > > NM .tmp_vmlinux.kallsyms3.syms >> > > > KSYMS .tmp_vmlinux.kallsyms3.S >> > > > AS .tmp_vmlinux.kallsyms3.S >> > > > LD vmlinux >> > > > BTFIDS vmlinux >> > > > FAILED: load BTF from vmlinux: No such file or directory >> > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >> > > > make[1]: *** Deleting file 'vmlinux' >> > > > make: *** [Makefile:1264: vmlinux] Error 2 >> > > > >> > > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >> > > > (2241ab53cb). >> > > > >> > > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >> > > > upstream pahole on master (02d67c5176) and upstream pahole on >> > > > next (2ca56f4c6f659). >> > > > >> > > > Of the above 6 combinations, I think I've tried all of them (maybe >> > > > missing 1 or 2). >> > > > >> > > > Looks like GCC got updated recently on my machine, so perhaps >> > > > it's related? >> > > > >> > > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >> > > > >> > > > I'll try some debugging, but just wanted to report it first. >> > > hi, >> > > I can't reproduce that.. can you reproduce it outside vmtest.sh? >> > > >> > > there will be lot of output with patch below, but could contain >> > > some more error output >> > Thanks for the hints. Doing a regular build outside of vmtest.sh >> > seems to work ok. So maybe it's a difference in the build config. >> > >> > I'll put a little more time into debugging to see if it goes anywhere. >> > But I'll have to get back to the regularly scheduled programming >> > soon. >> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >> in pahole when CONFIG_X86_KERNEL_IBT is set. > > could you plese attach your config and the build error? > I can't reproduce that I've confirmed that CONFIG_X86_KERNEL_IBT=n fixes my issue as well. Here is the config that produces my originally reported error: https://pastes.dxuuu.xyz/wlg9tb Thanks, Daniel ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-28 0:21 ` Daniel Xu @ 2023-01-28 0:23 ` Daniel Xu 0 siblings, 0 replies; 29+ messages in thread From: Daniel Xu @ 2023-01-28 0:23 UTC (permalink / raw) To: Jiri Olsa, Alexandre Peixoto Ferreira Cc: bpf@vger.kernel.org, Arnaldo Carvalho de Melo On Fri, Jan 27, 2023, at 5:21 PM, Daniel Xu wrote: > Hi Jiri & Alexandre, > > On Fri, Jan 27, 2023, at 5:00 PM, Jiri Olsa wrote: >> On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >>> >>> >>> On 1/24/23 00:13, Daniel Xu wrote: >>> > Hi Jiri, >>> > >>> > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >>> > > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>> > > > Hi, >>> > > > >>> > > > I'm getting the following error during build: >>> > > > >>> > > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>> > > > [...] >>> > > > BTF .btf.vmlinux.bin.o >>> > > > btf_encoder__encode: btf__dedup failed! >>> > > > Failed to encode BTF >>> > > > LD .tmp_vmlinux.kallsyms1 >>> > > > NM .tmp_vmlinux.kallsyms1.syms >>> > > > KSYMS .tmp_vmlinux.kallsyms1.S >>> > > > AS .tmp_vmlinux.kallsyms1.S >>> > > > LD .tmp_vmlinux.kallsyms2 >>> > > > NM .tmp_vmlinux.kallsyms2.syms >>> > > > KSYMS .tmp_vmlinux.kallsyms2.S >>> > > > AS .tmp_vmlinux.kallsyms2.S >>> > > > LD .tmp_vmlinux.kallsyms3 >>> > > > NM .tmp_vmlinux.kallsyms3.syms >>> > > > KSYMS .tmp_vmlinux.kallsyms3.S >>> > > > AS .tmp_vmlinux.kallsyms3.S >>> > > > LD vmlinux >>> > > > BTFIDS vmlinux >>> > > > FAILED: load BTF from vmlinux: No such file or directory >>> > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>> > > > make[1]: *** Deleting file 'vmlinux' >>> > > > make: *** [Makefile:1264: vmlinux] Error 2 >>> > > > >>> > > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>> > > > (2241ab53cb). >>> > > > >>> > > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>> > > > upstream pahole on master (02d67c5176) and upstream pahole on >>> > > > next (2ca56f4c6f659). >>> > > > >>> > > > Of the above 6 combinations, I think I've tried all of them (maybe >>> > > > missing 1 or 2). >>> > > > >>> > > > Looks like GCC got updated recently on my machine, so perhaps >>> > > > it's related? >>> > > > >>> > > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>> > > > >>> > > > I'll try some debugging, but just wanted to report it first. >>> > > hi, >>> > > I can't reproduce that.. can you reproduce it outside vmtest.sh? >>> > > >>> > > there will be lot of output with patch below, but could contain >>> > > some more error output >>> > Thanks for the hints. Doing a regular build outside of vmtest.sh >>> > seems to work ok. So maybe it's a difference in the build config. >>> > >>> > I'll put a little more time into debugging to see if it goes anywhere. >>> > But I'll have to get back to the regularly scheduled programming >>> > soon. >>> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >>> in pahole when CONFIG_X86_KERNEL_IBT is set. >> >> could you plese attach your config and the build error? >> I can't reproduce that > > I've confirmed that CONFIG_X86_KERNEL_IBT=n fixes my issue as well. > > Here is the config that produces my originally reported error: > https://pastes.dxuuu.xyz/wlg9tb > > Thanks, > Daniel Here's a patch that helps for me. Not sure if you want to apply this or fix the root cause in bpftool. --- From 3dc50f3dd45767cb8c3b32c1510c7064f20f80c1 Mon Sep 17 00:00:00 2001 Message-Id: <3dc50f3dd45767cb8c3b32c1510c7064f20f80c1.1674865319.git.dxu@dxuuu.xyz> From: Daniel Xu <dxu@dxuuu.xyz> Date: Fri, 27 Jan 2023 17:17:32 -0700 Subject: [PATCH] bpf, selftests: Disable CONFIG_X86_KERNEL_IBT for vmtest.sh CONFIG_X86_KERNEL_IBT=y was causing the following compile error: BTF .btf.vmlinux.bin.o btf_encoder__encode: btf__dedup failed! Failed to encode BTF LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.S LD .tmp_vmlinux.kallsyms2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.S LD .tmp_vmlinux.kallsyms3 NM .tmp_vmlinux.kallsyms3.syms KSYMS .tmp_vmlinux.kallsyms3.S AS .tmp_vmlinux.kallsyms3.S LD vmlinux BTFIDS vmlinux libbpf: failed to find '.BTF' ELF section in vmlinux FAILED: load BTF from vmlinux: No data available make[1]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 255 make[1]: *** Deleting file 'vmlinux' make: *** [Makefile:1252: vmlinux] Error 2 Disable for vmtests as we do not really need the extra security measures there. I suspect this was recently triggered by 4fd5f70ce14d ("x86/Kconfig: Enable kernel IBT by default"). Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> --- tools/testing/selftests/bpf/config.x86_64 | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/config.x86_64 b/tools/testing/selftests/bpf/config.x86_64 index dd97d61d325c..3026b1282cc7 100644 --- a/tools/testing/selftests/bpf/config.x86_64 +++ b/tools/testing/selftests/bpf/config.x86_64 @@ -237,6 +237,7 @@ CONFIG_VIRTIO_PCI=y CONFIG_VLAN_8021Q=y CONFIG_X86_ACPI_CPUFREQ=y CONFIG_X86_CPUID=y +CONFIG_X86_KERNEL_IBT=n CONFIG_X86_MSR=y CONFIG_X86_POWERNOW_K8=y CONFIG_XDP_SOCKETS_DIAG=y -- 2.39.1 ^ permalink raw reply related [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-28 0:00 ` Jiri Olsa 2023-01-28 0:21 ` Daniel Xu @ 2023-01-28 19:23 ` Alexandre Peixoto Ferreira 2023-01-31 15:18 ` Jiri Olsa 1 sibling, 1 reply; 29+ messages in thread From: Alexandre Peixoto Ferreira @ 2023-01-28 19:23 UTC (permalink / raw) To: Jiri Olsa; +Cc: Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo Jirka and Daniel, On 1/27/23 18:00, Jiri Olsa wrote: > On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >> >> On 1/24/23 00:13, Daniel Xu wrote: >>> Hi Jiri, >>> >>> On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >>>> On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>>>> Hi, >>>>> >>>>> I'm getting the following error during build: >>>>> >>>>> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>>>> [...] >>>>> BTF .btf.vmlinux.bin.o >>>>> btf_encoder__encode: btf__dedup failed! >>>>> Failed to encode BTF >>>>> LD .tmp_vmlinux.kallsyms1 >>>>> NM .tmp_vmlinux.kallsyms1.syms >>>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>>> AS .tmp_vmlinux.kallsyms1.S >>>>> LD .tmp_vmlinux.kallsyms2 >>>>> NM .tmp_vmlinux.kallsyms2.syms >>>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>>> AS .tmp_vmlinux.kallsyms2.S >>>>> LD .tmp_vmlinux.kallsyms3 >>>>> NM .tmp_vmlinux.kallsyms3.syms >>>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>>> AS .tmp_vmlinux.kallsyms3.S >>>>> LD vmlinux >>>>> BTFIDS vmlinux >>>>> FAILED: load BTF from vmlinux: No such file or directory >>>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>>> make[1]: *** Deleting file 'vmlinux' >>>>> make: *** [Makefile:1264: vmlinux] Error 2 >>>>> >>>>> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>>>> (2241ab53cb). >>>>> >>>>> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>>>> upstream pahole on master (02d67c5176) and upstream pahole on >>>>> next (2ca56f4c6f659). >>>>> >>>>> Of the above 6 combinations, I think I've tried all of them (maybe >>>>> missing 1 or 2). >>>>> >>>>> Looks like GCC got updated recently on my machine, so perhaps >>>>> it's related? >>>>> >>>>> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>>>> >>>>> I'll try some debugging, but just wanted to report it first. >>>> hi, >>>> I can't reproduce that.. can you reproduce it outside vmtest.sh? >>>> >>>> there will be lot of output with patch below, but could contain >>>> some more error output >>> Thanks for the hints. Doing a regular build outside of vmtest.sh >>> seems to work ok. So maybe it's a difference in the build config. >>> >>> I'll put a little more time into debugging to see if it goes anywhere. >>> But I'll have to get back to the regularly scheduled programming >>> soon. >> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >> in pahole when CONFIG_X86_KERNEL_IBT is set. > could you plese attach your config and the build error? > I can't reproduce that > > thanks, > jirka My working .config is available at https://pastebin.pl/view/bef3765c change CONFIG_X86_KERNEL_IBT to y to get the error. The error is similar to Daniel's and is shown below: LD .tmp_vmlinux.btf BTF .btf.vmlinux.bin.o btf_encoder__encode: btf__dedup failed! Failed to encode BTF LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.S LD .tmp_vmlinux.kallsyms2 NM .tmp_vmlinux.kallsyms2.syms KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.S LD .tmp_vmlinux.kallsyms3 NM .tmp_vmlinux.kallsyms3.syms KSYMS .tmp_vmlinux.kallsyms3.S AS .tmp_vmlinux.kallsyms3.S LD vmlinux BTFIDS vmlinux FAILED: load BTF from vmlinux: No such file or directory make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 make[1]: *** Deleting file 'vmlinux' make: *** [Makefile:1264: vmlinux] Error 2 Thanks, -- Alexandre Peixoto Ferreira ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-28 19:23 ` Alexandre Peixoto Ferreira @ 2023-01-31 15:18 ` Jiri Olsa 2023-02-09 0:21 ` Vicki Pfau 2023-02-09 4:15 ` Alexandre Peixoto Ferreira 0 siblings, 2 replies; 29+ messages in thread From: Jiri Olsa @ 2023-01-31 15:18 UTC (permalink / raw) To: Alexandre Peixoto Ferreira Cc: Jiri Olsa, Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: > Jirka and Daniel, > > On 1/27/23 18:00, Jiri Olsa wrote: > > On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: > > > > > > On 1/24/23 00:13, Daniel Xu wrote: > > > > Hi Jiri, > > > > > > > > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: > > > > > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: > > > > > > Hi, > > > > > > > > > > > > I'm getting the following error during build: > > > > > > > > > > > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 > > > > > > [...] > > > > > > BTF .btf.vmlinux.bin.o > > > > > > btf_encoder__encode: btf__dedup failed! > > > > > > Failed to encode BTF > > > > > > LD .tmp_vmlinux.kallsyms1 > > > > > > NM .tmp_vmlinux.kallsyms1.syms > > > > > > KSYMS .tmp_vmlinux.kallsyms1.S > > > > > > AS .tmp_vmlinux.kallsyms1.S > > > > > > LD .tmp_vmlinux.kallsyms2 > > > > > > NM .tmp_vmlinux.kallsyms2.syms > > > > > > KSYMS .tmp_vmlinux.kallsyms2.S > > > > > > AS .tmp_vmlinux.kallsyms2.S > > > > > > LD .tmp_vmlinux.kallsyms3 > > > > > > NM .tmp_vmlinux.kallsyms3.syms > > > > > > KSYMS .tmp_vmlinux.kallsyms3.S > > > > > > AS .tmp_vmlinux.kallsyms3.S > > > > > > LD vmlinux > > > > > > BTFIDS vmlinux > > > > > > FAILED: load BTF from vmlinux: No such file or directory > > > > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > > > > > make[1]: *** Deleting file 'vmlinux' > > > > > > make: *** [Makefile:1264: vmlinux] Error 2 > > > > > > > > > > > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 > > > > > > (2241ab53cb). > > > > > > > > > > > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as > > > > > > upstream pahole on master (02d67c5176) and upstream pahole on > > > > > > next (2ca56f4c6f659). > > > > > > > > > > > > Of the above 6 combinations, I think I've tried all of them (maybe > > > > > > missing 1 or 2). > > > > > > > > > > > > Looks like GCC got updated recently on my machine, so perhaps > > > > > > it's related? > > > > > > > > > > > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" > > > > > > > > > > > > I'll try some debugging, but just wanted to report it first. > > > > > hi, > > > > > I can't reproduce that.. can you reproduce it outside vmtest.sh? > > > > > > > > > > there will be lot of output with patch below, but could contain > > > > > some more error output > > > > Thanks for the hints. Doing a regular build outside of vmtest.sh > > > > seems to work ok. So maybe it's a difference in the build config. > > > > > > > > I'll put a little more time into debugging to see if it goes anywhere. > > > > But I'll have to get back to the regularly scheduled programming > > > > soon. > > > 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails > > > in pahole when CONFIG_X86_KERNEL_IBT is set. > > could you plese attach your config and the build error? > > I can't reproduce that > > > > thanks, > > jirka > > My working .config is available at https://pastebin.pl/view/bef3765c > change CONFIG_X86_KERNEL_IBT to y to get the error. > > The error is similar to Daniel's and is shown below: > > LD .tmp_vmlinux.btf > BTF .btf.vmlinux.bin.o > btf_encoder__encode: btf__dedup failed! > Failed to encode BTF > LD .tmp_vmlinux.kallsyms1 > NM .tmp_vmlinux.kallsyms1.syms > KSYMS .tmp_vmlinux.kallsyms1.S > AS .tmp_vmlinux.kallsyms1.S > LD .tmp_vmlinux.kallsyms2 > NM .tmp_vmlinux.kallsyms2.syms > KSYMS .tmp_vmlinux.kallsyms2.S > AS .tmp_vmlinux.kallsyms2.S > LD .tmp_vmlinux.kallsyms3 > NM .tmp_vmlinux.kallsyms3.syms > KSYMS .tmp_vmlinux.kallsyms3.S > AS .tmp_vmlinux.kallsyms3.S > LD vmlinux > BTFIDS vmlinux > FAILED: load BTF from vmlinux: No such file or directory > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > make[1]: *** Deleting file 'vmlinux' > make: *** [Makefile:1264: vmlinux] Error 2 I can't reproduce that.. I tried with gcc versions: gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) I haven't found fedora setup with 12.2.1 20230111 yet I tried alsa with latest pahole master branch were you guys able to get any more verbose output that I suggested earlier? jirka ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-31 15:18 ` Jiri Olsa @ 2023-02-09 0:21 ` Vicki Pfau 2023-02-09 4:15 ` Alexandre Peixoto Ferreira 1 sibling, 0 replies; 29+ messages in thread From: Vicki Pfau @ 2023-02-09 0:21 UTC (permalink / raw) To: Jiri Olsa Cc: Alexandre Peixoto Ferreira, Jiri Olsa, Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo Hello, I seem to be having a related problem trying to build Linux at all. This used to work, but after some recent upgrades (I am also running Arch Linux), I'm getting a dedup error too. I'm also getting a "relocation to !ENDBR" error that, as far as I can tell (and that's not particularly far, to be fair), is erroneous, which makes me think something even stranger is going on with my tools. Since both of these issues appeared, so far, only on Arch Linux, it might be an Arch-speciifc packaging issue. I've uploaded my config and pahole log to the following URLs: https://endrift.com/files/config.gz https://endrift.com/files/make-log.xz Vicki PS: My apologies for the lack of a quoted reply or any other formatting issues; I'm not subscribed to this mailing list and am struggling to figure out how to send a reply without the originals in my client. In retrospect, maybe I could have imported the .eml/mbox directly. ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-01-31 15:18 ` Jiri Olsa 2023-02-09 0:21 ` Vicki Pfau @ 2023-02-09 4:15 ` Alexandre Peixoto Ferreira 2023-02-09 13:07 ` Alan Maguire 1 sibling, 1 reply; 29+ messages in thread From: Alexandre Peixoto Ferreira @ 2023-02-09 4:15 UTC (permalink / raw) To: Jiri Olsa; +Cc: Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo Jiri, On 1/31/23 09:18, Jiri Olsa wrote: > On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: >> Jirka and Daniel, >> >> On 1/27/23 18:00, Jiri Olsa wrote: >>> On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >>>> On 1/24/23 00:13, Daniel Xu wrote: >>>>> Hi Jiri, >>>>> >>>>> On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >>>>>> On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>>>>>> Hi, >>>>>>> >>>>>>> I'm getting the following error during build: >>>>>>> >>>>>>> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>>>>>> [...] >>>>>>> BTF .btf.vmlinux.bin.o >>>>>>> btf_encoder__encode: btf__dedup failed! >>>>>>> Failed to encode BTF >>>>>>> LD .tmp_vmlinux.kallsyms1 >>>>>>> NM .tmp_vmlinux.kallsyms1.syms >>>>>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>>>>> AS .tmp_vmlinux.kallsyms1.S >>>>>>> LD .tmp_vmlinux.kallsyms2 >>>>>>> NM .tmp_vmlinux.kallsyms2.syms >>>>>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>>>>> AS .tmp_vmlinux.kallsyms2.S >>>>>>> LD .tmp_vmlinux.kallsyms3 >>>>>>> NM .tmp_vmlinux.kallsyms3.syms >>>>>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>>>>> AS .tmp_vmlinux.kallsyms3.S >>>>>>> LD vmlinux >>>>>>> BTFIDS vmlinux >>>>>>> FAILED: load BTF from vmlinux: No such file or directory >>>>>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>>>>> make[1]: *** Deleting file 'vmlinux' >>>>>>> make: *** [Makefile:1264: vmlinux] Error 2 >>>>>>> >>>>>>> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>>>>>> (2241ab53cb). >>>>>>> >>>>>>> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>>>>>> upstream pahole on master (02d67c5176) and upstream pahole on >>>>>>> next (2ca56f4c6f659). >>>>>>> >>>>>>> Of the above 6 combinations, I think I've tried all of them (maybe >>>>>>> missing 1 or 2). >>>>>>> >>>>>>> Looks like GCC got updated recently on my machine, so perhaps >>>>>>> it's related? >>>>>>> >>>>>>> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>>>>>> >>>>>>> I'll try some debugging, but just wanted to report it first. >>>>>> hi, >>>>>> I can't reproduce that.. can you reproduce it outside vmtest.sh? >>>>>> >>>>>> there will be lot of output with patch below, but could contain >>>>>> some more error output >>>>> Thanks for the hints. Doing a regular build outside of vmtest.sh >>>>> seems to work ok. So maybe it's a difference in the build config. >>>>> >>>>> I'll put a little more time into debugging to see if it goes anywhere. >>>>> But I'll have to get back to the regularly scheduled programming >>>>> soon. >>>> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >>>> in pahole when CONFIG_X86_KERNEL_IBT is set. >>> could you plese attach your config and the build error? >>> I can't reproduce that >>> >>> thanks, >>> jirka >> My working .config is available at https://pastebin.pl/view/bef3765c >> change CONFIG_X86_KERNEL_IBT to y to get the error. >> >> The error is similar to Daniel's and is shown below: >> >> LD .tmp_vmlinux.btf >> BTF .btf.vmlinux.bin.o >> btf_encoder__encode: btf__dedup failed! >> Failed to encode BTF >> LD .tmp_vmlinux.kallsyms1 >> NM .tmp_vmlinux.kallsyms1.syms >> KSYMS .tmp_vmlinux.kallsyms1.S >> AS .tmp_vmlinux.kallsyms1.S >> LD .tmp_vmlinux.kallsyms2 >> NM .tmp_vmlinux.kallsyms2.syms >> KSYMS .tmp_vmlinux.kallsyms2.S >> AS .tmp_vmlinux.kallsyms2.S >> LD .tmp_vmlinux.kallsyms3 >> NM .tmp_vmlinux.kallsyms3.syms >> KSYMS .tmp_vmlinux.kallsyms3.S >> AS .tmp_vmlinux.kallsyms3.S >> LD vmlinux >> BTFIDS vmlinux >> FAILED: load BTF from vmlinux: No such file or directory >> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >> make[1]: *** Deleting file 'vmlinux' >> make: *** [Makefile:1264: vmlinux] Error 2 > I can't reproduce that.. I tried with gcc versions: > > gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) > gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) > > I haven't found fedora setup with 12.2.1 20230111 yet > > I tried alsa with latest pahole master branch > > were you guys able to get any more verbose output > that I suggested earlier? > > jirka I compiled with and without IBT using the -V on pahole (LLVM_OBJCOPY=objcopy pahole -V -J --btf_gen_floats -j .tmp_vmlinux.btf) and the outfiles are a little too big (540MB). The error happens with this CONST type pointing to itself. That does not happen with the IBT option removed. $ grep -n "CONST (anon) type_id" /tmp/with_IBT | more 346:[2] CONST (anon) type_id=2 349:[5] CONST (anon) type_id=5 351:[7] CONST (anon) type_id=7 356:[12] CONST (anon) type_id=12 363:[19] CONST (anon) type_id=19 373:[29] CONST (anon) type_id=29 375:[31] CONST (anon) type_id=31 409:[63] CONST (anon) type_id=63 444:[89] CONST (anon) type_id=0 472:[97] CONST (anon) type_id=97 616:[129] CONST (anon) type_id=129 652:[131] CONST (anon) type_id=131 1319:[234] CONST (anon) type_id=234 1372:[246] CONST (anon) type_id=246 .... $diff -ru with_IBT without_IBT --- with_IBT 2023-01-31 09:39:24.915912735 -0600 +++ without_IBT 2023-01-31 09:46:23.456005278 -0600 @@ -340,346 +340,14800 @@ Found per-CPU symbol 'cpu_tlbstate_shared' at address 0x2c040 Found per-CPU symbol 'mce_poll_banks' at address 0x1ad20 Found 341 per-CPU variables! -Found 61470 functions! +Found 61462 functions! +File .tmp_vmlinux.btf: +[1] FUNC_PROTO (anon) return=0 args=(void) +[2] FUNC verify_cpu type_id=1 +[3] FUNC_PROTO (anon) return=0 args=(void) +[4] FUNC sev_verify_cbit type_id=3 +search cu 'arch/x86/kernel/head_64.S' for percpu global variables. +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 +Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 +Found per-CPU symbol 'last_nmi_rip' at address 0x1a018 +Found per-CPU symbol 'nmi_stats' at address 0x1a030 +Found per-CPU symbol 'swallow_nmi' at address 0x1a020 +Found per-CPU symbol 'nmi_state' at address 0x1a010 +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 +Found per-CPU symbol 'nmi_cr2' at address 0x1a008 +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 ... And the lines 342-365 of the with_IBT result: 342 Found 341 per-CPU variables! 343 Found 61470 functions! 344 File .tmp_vmlinux.btf: 345 [1] INT long unsigned int size=8 nr_bits=64 encoding=(none) 346 [2] CONST (anon) type_id=2 347 [3] PTR (anon) type_id=6 348 [4] INT char size=1 nr_bits=8 encoding=(none) 349 [5] CONST (anon) type_id=5 350 [6] INT unsigned int size=4 nr_bits=32 encoding=(none) 351 [7] CONST (anon) type_id=7 352 [8] TYPEDEF __s8 type_id=10 353 [9] INT signed char size=1 nr_bits=8 encoding=SIGNED 354 [10] TYPEDEF __u8 type_id=12 355 [11] INT unsigned char size=1 nr_bits=8 encoding=(none) 356 [12] CONST (anon) type_id=12 357 [13] TYPEDEF __s16 type_id=15 358 [14] INT short int size=2 nr_bits=16 encoding=SIGNED 359 [15] TYPEDEF __u16 type_id=17 360 [16] INT short unsigned int size=2 nr_bits=16 encoding=(none) 361 [17] TYPEDEF __s32 type_id=19 362 [18] INT int size=4 nr_bits=32 encoding=SIGNED 363 [19] CONST (anon) type_id=19 364 [20] TYPEDEF __u32 type_id=7 365 [21] TYPEDEF __s64 type_id=23 lines 342-362 of without_IBT 342 Found 341 per-CPU variables! 343 Found 61462 functions! 344 File .tmp_vmlinux.btf: 345 [1] FUNC_PROTO (anon) return=0 args=(void) 346 [2] FUNC verify_cpu type_id=1 347 [3] FUNC_PROTO (anon) return=0 args=(void) 348 [4] FUNC sev_verify_cbit type_id=3 349 search cu 'arch/x86/kernel/head_64.S' for percpu global variables. 350 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 351 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 352 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 353 Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 354 Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 355 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 356 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 357 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 358 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 359 Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 360 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 361 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 362 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 If the full debug files are useful or a target grep or diff is better let me know. Thanks, -- Alexandre Peixoto Ferreira ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-02-09 4:15 ` Alexandre Peixoto Ferreira @ 2023-02-09 13:07 ` Alan Maguire 2023-02-10 14:02 ` Alexandre Peixoto Ferreira 0 siblings, 1 reply; 29+ messages in thread From: Alan Maguire @ 2023-02-09 13:07 UTC (permalink / raw) To: Alexandre Peixoto Ferreira, Jiri Olsa Cc: Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo On 09/02/2023 04:15, Alexandre Peixoto Ferreira wrote: > Jiri, > > On 1/31/23 09:18, Jiri Olsa wrote: >> On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: >>> Jirka and Daniel, >>> >>> On 1/27/23 18:00, Jiri Olsa wrote: >>>> On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >>>>> On 1/24/23 00:13, Daniel Xu wrote: >>>>>> Hi Jiri, >>>>>> >>>>>> On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >>>>>>> On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>>>>>>> Hi, >>>>>>>> >>>>>>>> I'm getting the following error during build: >>>>>>>> >>>>>>>> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>>>>>>> [...] >>>>>>>> BTF .btf.vmlinux.bin.o >>>>>>>> btf_encoder__encode: btf__dedup failed! >>>>>>>> Failed to encode BTF >>>>>>>> LD .tmp_vmlinux.kallsyms1 >>>>>>>> NM .tmp_vmlinux.kallsyms1.syms >>>>>>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>>>>>> AS .tmp_vmlinux.kallsyms1.S >>>>>>>> LD .tmp_vmlinux.kallsyms2 >>>>>>>> NM .tmp_vmlinux.kallsyms2.syms >>>>>>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>>>>>> AS .tmp_vmlinux.kallsyms2.S >>>>>>>> LD .tmp_vmlinux.kallsyms3 >>>>>>>> NM .tmp_vmlinux.kallsyms3.syms >>>>>>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>>>>>> AS .tmp_vmlinux.kallsyms3.S >>>>>>>> LD vmlinux >>>>>>>> BTFIDS vmlinux >>>>>>>> FAILED: load BTF from vmlinux: No such file or directory >>>>>>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>>>>>> make[1]: *** Deleting file 'vmlinux' >>>>>>>> make: *** [Makefile:1264: vmlinux] Error 2 >>>>>>>> >>>>>>>> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>>>>>>> (2241ab53cb). >>>>>>>> >>>>>>>> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>>>>>>> upstream pahole on master (02d67c5176) and upstream pahole on >>>>>>>> next (2ca56f4c6f659). >>>>>>>> >>>>>>>> Of the above 6 combinations, I think I've tried all of them (maybe >>>>>>>> missing 1 or 2). >>>>>>>> >>>>>>>> Looks like GCC got updated recently on my machine, so perhaps >>>>>>>> it's related? >>>>>>>> >>>>>>>> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>>>>>>> >>>>>>>> I'll try some debugging, but just wanted to report it first. >>>>>>> hi, >>>>>>> I can't reproduce that.. can you reproduce it outside vmtest.sh? >>>>>>> >>>>>>> there will be lot of output with patch below, but could contain >>>>>>> some more error output >>>>>> Thanks for the hints. Doing a regular build outside of vmtest.sh >>>>>> seems to work ok. So maybe it's a difference in the build config. >>>>>> >>>>>> I'll put a little more time into debugging to see if it goes anywhere. >>>>>> But I'll have to get back to the regularly scheduled programming >>>>>> soon. >>>>> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >>>>> in pahole when CONFIG_X86_KERNEL_IBT is set. >>>> could you plese attach your config and the build error? >>>> I can't reproduce that >>>> >>>> thanks, >>>> jirka >>> My working .config is available at https://pastebin.pl/view/bef3765c >>> change CONFIG_X86_KERNEL_IBT to y to get the error. >>> >>> The error is similar to Daniel's and is shown below: >>> >>> LD .tmp_vmlinux.btf >>> BTF .btf.vmlinux.bin.o >>> btf_encoder__encode: btf__dedup failed! >>> Failed to encode BTF >>> LD .tmp_vmlinux.kallsyms1 >>> NM .tmp_vmlinux.kallsyms1.syms >>> KSYMS .tmp_vmlinux.kallsyms1.S >>> AS .tmp_vmlinux.kallsyms1.S >>> LD .tmp_vmlinux.kallsyms2 >>> NM .tmp_vmlinux.kallsyms2.syms >>> KSYMS .tmp_vmlinux.kallsyms2.S >>> AS .tmp_vmlinux.kallsyms2.S >>> LD .tmp_vmlinux.kallsyms3 >>> NM .tmp_vmlinux.kallsyms3.syms >>> KSYMS .tmp_vmlinux.kallsyms3.S >>> AS .tmp_vmlinux.kallsyms3.S >>> LD vmlinux >>> BTFIDS vmlinux >>> FAILED: load BTF from vmlinux: No such file or directory >>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>> make[1]: *** Deleting file 'vmlinux' >>> make: *** [Makefile:1264: vmlinux] Error 2 >> I can't reproduce that.. I tried with gcc versions: >> >> gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) >> gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) >> >> I haven't found fedora setup with 12.2.1 20230111 yet >> >> I tried alsa with latest pahole master branch >> >> were you guys able to get any more verbose output >> that I suggested earlier? >> >> jirka > > I compiled with and without IBT using the -V on pahole (LLVM_OBJCOPY=objcopy pahole -V -J --btf_gen_floats -j .tmp_vmlinux.btf) and the outfiles are a little too big (540MB). The error happens with this CONST type pointing to itself. That does not happen with the IBT option removed. > > $ grep -n "CONST (anon) type_id" /tmp/with_IBT | more > 346:[2] CONST (anon) type_id=2 > 349:[5] CONST (anon) type_id=5 > 351:[7] CONST (anon) type_id=7 > 356:[12] CONST (anon) type_id=12 > 363:[19] CONST (anon) type_id=19 > 373:[29] CONST (anon) type_id=29 > 375:[31] CONST (anon) type_id=31 > 409:[63] CONST (anon) type_id=63 > 444:[89] CONST (anon) type_id=0 > 472:[97] CONST (anon) type_id=97 > 616:[129] CONST (anon) type_id=129 > 652:[131] CONST (anon) type_id=131 > 1319:[234] CONST (anon) type_id=234 > 1372:[246] CONST (anon) type_id=246 > .... > > $diff -ru with_IBT without_IBT > --- with_IBT 2023-01-31 09:39:24.915912735 -0600 > +++ without_IBT 2023-01-31 09:46:23.456005278 -0600 > @@ -340,346 +340,14800 @@ > Found per-CPU symbol 'cpu_tlbstate_shared' at address 0x2c040 > Found per-CPU symbol 'mce_poll_banks' at address 0x1ad20 > Found 341 per-CPU variables! > -Found 61470 functions! > +Found 61462 functions! > +File .tmp_vmlinux.btf: > +[1] FUNC_PROTO (anon) return=0 args=(void) > +[2] FUNC verify_cpu type_id=1 > +[3] FUNC_PROTO (anon) return=0 args=(void) > +[4] FUNC sev_verify_cbit type_id=3 > +search cu 'arch/x86/kernel/head_64.S' for percpu global variables. > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > +Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > +Found per-CPU symbol 'last_nmi_rip' at address 0x1a018 > +Found per-CPU symbol 'nmi_stats' at address 0x1a030 > +Found per-CPU symbol 'swallow_nmi' at address 0x1a020 > +Found per-CPU symbol 'nmi_state' at address 0x1a010 > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > +Found per-CPU symbol 'nmi_cr2' at address 0x1a008 > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > ... > > And the lines 342-365 of the with_IBT result: > 342 Found 341 per-CPU variables! > 343 Found 61470 functions! > 344 File .tmp_vmlinux.btf: > 345 [1] INT long unsigned int size=8 nr_bits=64 encoding=(none) > 346 [2] CONST (anon) type_id=2 > 347 [3] PTR (anon) type_id=6 > 348 [4] INT char size=1 nr_bits=8 encoding=(none) > 349 [5] CONST (anon) type_id=5 > 350 [6] INT unsigned int size=4 nr_bits=32 encoding=(none) > 351 [7] CONST (anon) type_id=7 > 352 [8] TYPEDEF __s8 type_id=10 > 353 [9] INT signed char size=1 nr_bits=8 encoding=SIGNED > 354 [10] TYPEDEF __u8 type_id=12 > 355 [11] INT unsigned char size=1 nr_bits=8 encoding=(none) > 356 [12] CONST (anon) type_id=12 > 357 [13] TYPEDEF __s16 type_id=15 > 358 [14] INT short int size=2 nr_bits=16 encoding=SIGNED > 359 [15] TYPEDEF __u16 type_id=17 > 360 [16] INT short unsigned int size=2 nr_bits=16 encoding=(none) > 361 [17] TYPEDEF __s32 type_id=19 > 362 [18] INT int size=4 nr_bits=32 encoding=SIGNED > 363 [19] CONST (anon) type_id=19 > 364 [20] TYPEDEF __u32 type_id=7 > 365 [21] TYPEDEF __s64 type_id=23 > > lines 342-362 of without_IBT > > 342 Found 341 per-CPU variables! > 343 Found 61462 functions! > 344 File .tmp_vmlinux.btf: > 345 [1] FUNC_PROTO (anon) return=0 args=(void) > 346 [2] FUNC verify_cpu type_id=1 > 347 [3] FUNC_PROTO (anon) return=0 args=(void) > 348 [4] FUNC sev_verify_cbit type_id=3 > 349 search cu 'arch/x86/kernel/head_64.S' for percpu global variables. > 350 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > 351 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > 352 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > 353 Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > 354 Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > 355 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > 356 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > 357 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > 358 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > 359 Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 > 360 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > 361 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > 362 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > If the full debug files are useful or a target grep or diff is better let me know. > I managed to reproduce this too with IBT enabled; one thing I noticed is with pahole built with an up-to-date libbpf and the changes in https://github.com/acmel/dwarves/tree/next, the problem went away. I didn't have time to root-cause it yet however. Not sure if you're in a position to do this, but if you can, would you mind building pahole from https://github.com/acmel/dwarves/tree/next ...and re-testing to see if that helps? Thanks! Alan > Thanks, > ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-02-09 13:07 ` Alan Maguire @ 2023-02-10 14:02 ` Alexandre Peixoto Ferreira 2023-02-10 14:34 ` Jiri Olsa 0 siblings, 1 reply; 29+ messages in thread From: Alexandre Peixoto Ferreira @ 2023-02-10 14:02 UTC (permalink / raw) To: Alan Maguire, Jiri Olsa Cc: Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo Alam, On 2/9/23 07:07, Alan Maguire wrote: > On 09/02/2023 04:15, Alexandre Peixoto Ferreira wrote: >> Jiri, >> >> On 1/31/23 09:18, Jiri Olsa wrote: >>> On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: >>>> Jirka and Daniel, >>>> >>>> On 1/27/23 18:00, Jiri Olsa wrote: >>>>> On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >>>>>> On 1/24/23 00:13, Daniel Xu wrote: >>>>>>> Hi Jiri, >>>>>>> >>>>>>> On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >>>>>>>> On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>>>>>>>> Hi, >>>>>>>>> >>>>>>>>> I'm getting the following error during build: >>>>>>>>> >>>>>>>>> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>>>>>>>> [...] >>>>>>>>> BTF .btf.vmlinux.bin.o >>>>>>>>> btf_encoder__encode: btf__dedup failed! >>>>>>>>> Failed to encode BTF >>>>>>>>> LD .tmp_vmlinux.kallsyms1 >>>>>>>>> NM .tmp_vmlinux.kallsyms1.syms >>>>>>>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>>>>>>> AS .tmp_vmlinux.kallsyms1.S >>>>>>>>> LD .tmp_vmlinux.kallsyms2 >>>>>>>>> NM .tmp_vmlinux.kallsyms2.syms >>>>>>>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>>>>>>> AS .tmp_vmlinux.kallsyms2.S >>>>>>>>> LD .tmp_vmlinux.kallsyms3 >>>>>>>>> NM .tmp_vmlinux.kallsyms3.syms >>>>>>>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>>>>>>> AS .tmp_vmlinux.kallsyms3.S >>>>>>>>> LD vmlinux >>>>>>>>> BTFIDS vmlinux >>>>>>>>> FAILED: load BTF from vmlinux: No such file or directory >>>>>>>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>>>>>>> make[1]: *** Deleting file 'vmlinux' >>>>>>>>> make: *** [Makefile:1264: vmlinux] Error 2 >>>>>>>>> >>>>>>>>> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>>>>>>>> (2241ab53cb). >>>>>>>>> >>>>>>>>> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>>>>>>>> upstream pahole on master (02d67c5176) and upstream pahole on >>>>>>>>> next (2ca56f4c6f659). >>>>>>>>> >>>>>>>>> Of the above 6 combinations, I think I've tried all of them (maybe >>>>>>>>> missing 1 or 2). >>>>>>>>> >>>>>>>>> Looks like GCC got updated recently on my machine, so perhaps >>>>>>>>> it's related? >>>>>>>>> >>>>>>>>> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>>>>>>>> >>>>>>>>> I'll try some debugging, but just wanted to report it first. >>>>>>>> hi, >>>>>>>> I can't reproduce that.. can you reproduce it outside vmtest.sh? >>>>>>>> >>>>>>>> there will be lot of output with patch below, but could contain >>>>>>>> some more error output >>>>>>> Thanks for the hints. Doing a regular build outside of vmtest.sh >>>>>>> seems to work ok. So maybe it's a difference in the build config. >>>>>>> >>>>>>> I'll put a little more time into debugging to see if it goes anywhere. >>>>>>> But I'll have to get back to the regularly scheduled programming >>>>>>> soon. >>>>>> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >>>>>> in pahole when CONFIG_X86_KERNEL_IBT is set. >>>>> could you plese attach your config and the build error? >>>>> I can't reproduce that >>>>> >>>>> thanks, >>>>> jirka >>>> My working .config is available at https://pastebin.pl/view/bef3765c >>>> change CONFIG_X86_KERNEL_IBT to y to get the error. >>>> >>>> The error is similar to Daniel's and is shown below: >>>> >>>> LD .tmp_vmlinux.btf >>>> BTF .btf.vmlinux.bin.o >>>> btf_encoder__encode: btf__dedup failed! >>>> Failed to encode BTF >>>> LD .tmp_vmlinux.kallsyms1 >>>> NM .tmp_vmlinux.kallsyms1.syms >>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>> AS .tmp_vmlinux.kallsyms1.S >>>> LD .tmp_vmlinux.kallsyms2 >>>> NM .tmp_vmlinux.kallsyms2.syms >>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>> AS .tmp_vmlinux.kallsyms2.S >>>> LD .tmp_vmlinux.kallsyms3 >>>> NM .tmp_vmlinux.kallsyms3.syms >>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>> AS .tmp_vmlinux.kallsyms3.S >>>> LD vmlinux >>>> BTFIDS vmlinux >>>> FAILED: load BTF from vmlinux: No such file or directory >>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>> make[1]: *** Deleting file 'vmlinux' >>>> make: *** [Makefile:1264: vmlinux] Error 2 >>> I can't reproduce that.. I tried with gcc versions: >>> >>> gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) >>> gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) >>> >>> I haven't found fedora setup with 12.2.1 20230111 yet >>> >>> I tried alsa with latest pahole master branch >>> >>> were you guys able to get any more verbose output >>> that I suggested earlier? >>> >>> jirka >> I compiled with and without IBT using the -V on pahole (LLVM_OBJCOPY=objcopy pahole -V -J --btf_gen_floats -j .tmp_vmlinux.btf) and the outfiles are a little too big (540MB). The error happens with this CONST type pointing to itself. That does not happen with the IBT option removed. >> >> $ grep -n "CONST (anon) type_id" /tmp/with_IBT | more >> 346:[2] CONST (anon) type_id=2 >> 349:[5] CONST (anon) type_id=5 >> 351:[7] CONST (anon) type_id=7 >> 356:[12] CONST (anon) type_id=12 >> 363:[19] CONST (anon) type_id=19 >> 373:[29] CONST (anon) type_id=29 >> 375:[31] CONST (anon) type_id=31 >> 409:[63] CONST (anon) type_id=63 >> 444:[89] CONST (anon) type_id=0 >> 472:[97] CONST (anon) type_id=97 >> 616:[129] CONST (anon) type_id=129 >> 652:[131] CONST (anon) type_id=131 >> 1319:[234] CONST (anon) type_id=234 >> 1372:[246] CONST (anon) type_id=246 >> .... >> >> $diff -ru with_IBT without_IBT >> --- with_IBT 2023-01-31 09:39:24.915912735 -0600 >> +++ without_IBT 2023-01-31 09:46:23.456005278 -0600 >> @@ -340,346 +340,14800 @@ >> Found per-CPU symbol 'cpu_tlbstate_shared' at address 0x2c040 >> Found per-CPU symbol 'mce_poll_banks' at address 0x1ad20 >> Found 341 per-CPU variables! >> -Found 61470 functions! >> +Found 61462 functions! >> +File .tmp_vmlinux.btf: >> +[1] FUNC_PROTO (anon) return=0 args=(void) >> +[2] FUNC verify_cpu type_id=1 >> +[3] FUNC_PROTO (anon) return=0 args=(void) >> +[4] FUNC sev_verify_cbit type_id=3 >> +search cu 'arch/x86/kernel/head_64.S' for percpu global variables. >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >> +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> +Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >> +Found per-CPU symbol 'last_nmi_rip' at address 0x1a018 >> +Found per-CPU symbol 'nmi_stats' at address 0x1a030 >> +Found per-CPU symbol 'swallow_nmi' at address 0x1a020 >> +Found per-CPU symbol 'nmi_state' at address 0x1a010 >> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> +Found per-CPU symbol 'nmi_cr2' at address 0x1a008 >> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> ... >> >> And the lines 342-365 of the with_IBT result: >> 342 Found 341 per-CPU variables! >> 343 Found 61470 functions! >> 344 File .tmp_vmlinux.btf: >> 345 [1] INT long unsigned int size=8 nr_bits=64 encoding=(none) >> 346 [2] CONST (anon) type_id=2 >> 347 [3] PTR (anon) type_id=6 >> 348 [4] INT char size=1 nr_bits=8 encoding=(none) >> 349 [5] CONST (anon) type_id=5 >> 350 [6] INT unsigned int size=4 nr_bits=32 encoding=(none) >> 351 [7] CONST (anon) type_id=7 >> 352 [8] TYPEDEF __s8 type_id=10 >> 353 [9] INT signed char size=1 nr_bits=8 encoding=SIGNED >> 354 [10] TYPEDEF __u8 type_id=12 >> 355 [11] INT unsigned char size=1 nr_bits=8 encoding=(none) >> 356 [12] CONST (anon) type_id=12 >> 357 [13] TYPEDEF __s16 type_id=15 >> 358 [14] INT short int size=2 nr_bits=16 encoding=SIGNED >> 359 [15] TYPEDEF __u16 type_id=17 >> 360 [16] INT short unsigned int size=2 nr_bits=16 encoding=(none) >> 361 [17] TYPEDEF __s32 type_id=19 >> 362 [18] INT int size=4 nr_bits=32 encoding=SIGNED >> 363 [19] CONST (anon) type_id=19 >> 364 [20] TYPEDEF __u32 type_id=7 >> 365 [21] TYPEDEF __s64 type_id=23 >> >> lines 342-362 of without_IBT >> >> 342 Found 341 per-CPU variables! >> 343 Found 61462 functions! >> 344 File .tmp_vmlinux.btf: >> 345 [1] FUNC_PROTO (anon) return=0 args=(void) >> 346 [2] FUNC verify_cpu type_id=1 >> 347 [3] FUNC_PROTO (anon) return=0 args=(void) >> 348 [4] FUNC sev_verify_cbit type_id=3 >> 349 search cu 'arch/x86/kernel/head_64.S' for percpu global variables. >> 350 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> 351 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> 352 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> 353 Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >> 354 Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >> 355 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> 356 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> 357 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> 358 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >> 359 Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 >> 360 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> 361 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >> 362 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >> >> If the full debug files are useful or a target grep or diff is better let me know. >> > I managed to reproduce this too with IBT enabled; one thing I > noticed is with pahole built with an up-to-date libbpf and the > changes in https://github.com/acmel/dwarves/tree/next, the problem > went away. I didn't have time to root-cause it yet however. > > Not sure if you're in a position to do this, but if you can, > would you mind building pahole from > > https://github.com/acmel/dwarves/tree/next > > ...and re-testing to see if that helps? Thanks! > > Alan > >> Thanks, >> I tried with libbpf compiled from master https://github.com/libbpf/libbpf.git and pahole compiled from next branch on https://github.com/acmel/dwarve with the same result. With IBT enabled pahole fails and removing it results in a successful kernel. Alex, -- Alexandre Peixoto Ferreira ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-02-10 14:02 ` Alexandre Peixoto Ferreira @ 2023-02-10 14:34 ` Jiri Olsa 2023-02-10 15:37 ` Alexandre Ferreira 0 siblings, 1 reply; 29+ messages in thread From: Jiri Olsa @ 2023-02-10 14:34 UTC (permalink / raw) To: Alexandre Peixoto Ferreira Cc: Alan Maguire, Jiri Olsa, Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo On Fri, Feb 10, 2023 at 08:02:23AM -0600, Alexandre Peixoto Ferreira wrote: > Alam, > > On 2/9/23 07:07, Alan Maguire wrote: > > On 09/02/2023 04:15, Alexandre Peixoto Ferreira wrote: > > > Jiri, > > > > > > On 1/31/23 09:18, Jiri Olsa wrote: > > > > On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: > > > > > Jirka and Daniel, > > > > > > > > > > On 1/27/23 18:00, Jiri Olsa wrote: > > > > > > On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: > > > > > > > On 1/24/23 00:13, Daniel Xu wrote: > > > > > > > > Hi Jiri, > > > > > > > > > > > > > > > > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: > > > > > > > > > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > > > > > I'm getting the following error during build: > > > > > > > > > > > > > > > > > > > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 > > > > > > > > > > [...] > > > > > > > > > > BTF .btf.vmlinux.bin.o > > > > > > > > > > btf_encoder__encode: btf__dedup failed! > > > > > > > > > > Failed to encode BTF > > > > > > > > > > LD .tmp_vmlinux.kallsyms1 > > > > > > > > > > NM .tmp_vmlinux.kallsyms1.syms > > > > > > > > > > KSYMS .tmp_vmlinux.kallsyms1.S > > > > > > > > > > AS .tmp_vmlinux.kallsyms1.S > > > > > > > > > > LD .tmp_vmlinux.kallsyms2 > > > > > > > > > > NM .tmp_vmlinux.kallsyms2.syms > > > > > > > > > > KSYMS .tmp_vmlinux.kallsyms2.S > > > > > > > > > > AS .tmp_vmlinux.kallsyms2.S > > > > > > > > > > LD .tmp_vmlinux.kallsyms3 > > > > > > > > > > NM .tmp_vmlinux.kallsyms3.syms > > > > > > > > > > KSYMS .tmp_vmlinux.kallsyms3.S > > > > > > > > > > AS .tmp_vmlinux.kallsyms3.S > > > > > > > > > > LD vmlinux > > > > > > > > > > BTFIDS vmlinux > > > > > > > > > > FAILED: load BTF from vmlinux: No such file or directory > > > > > > > > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > > > > > > > > > make[1]: *** Deleting file 'vmlinux' > > > > > > > > > > make: *** [Makefile:1264: vmlinux] Error 2 > > > > > > > > > > > > > > > > > > > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 > > > > > > > > > > (2241ab53cb). > > > > > > > > > > > > > > > > > > > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as > > > > > > > > > > upstream pahole on master (02d67c5176) and upstream pahole on > > > > > > > > > > next (2ca56f4c6f659). > > > > > > > > > > > > > > > > > > > > Of the above 6 combinations, I think I've tried all of them (maybe > > > > > > > > > > missing 1 or 2). > > > > > > > > > > > > > > > > > > > > Looks like GCC got updated recently on my machine, so perhaps > > > > > > > > > > it's related? > > > > > > > > > > > > > > > > > > > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" > > > > > > > > > > > > > > > > > > > > I'll try some debugging, but just wanted to report it first. > > > > > > > > > hi, > > > > > > > > > I can't reproduce that.. can you reproduce it outside vmtest.sh? > > > > > > > > > > > > > > > > > > there will be lot of output with patch below, but could contain > > > > > > > > > some more error output > > > > > > > > Thanks for the hints. Doing a regular build outside of vmtest.sh > > > > > > > > seems to work ok. So maybe it's a difference in the build config. > > > > > > > > > > > > > > > > I'll put a little more time into debugging to see if it goes anywhere. > > > > > > > > But I'll have to get back to the regularly scheduled programming > > > > > > > > soon. > > > > > > > 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails > > > > > > > in pahole when CONFIG_X86_KERNEL_IBT is set. > > > > > > could you plese attach your config and the build error? > > > > > > I can't reproduce that > > > > > > > > > > > > thanks, > > > > > > jirka > > > > > My working .config is available at https://pastebin.pl/view/bef3765c > > > > > change CONFIG_X86_KERNEL_IBT to y to get the error. > > > > > > > > > > The error is similar to Daniel's and is shown below: > > > > > > > > > > LD .tmp_vmlinux.btf > > > > > BTF .btf.vmlinux.bin.o > > > > > btf_encoder__encode: btf__dedup failed! > > > > > Failed to encode BTF > > > > > LD .tmp_vmlinux.kallsyms1 > > > > > NM .tmp_vmlinux.kallsyms1.syms > > > > > KSYMS .tmp_vmlinux.kallsyms1.S > > > > > AS .tmp_vmlinux.kallsyms1.S > > > > > LD .tmp_vmlinux.kallsyms2 > > > > > NM .tmp_vmlinux.kallsyms2.syms > > > > > KSYMS .tmp_vmlinux.kallsyms2.S > > > > > AS .tmp_vmlinux.kallsyms2.S > > > > > LD .tmp_vmlinux.kallsyms3 > > > > > NM .tmp_vmlinux.kallsyms3.syms > > > > > KSYMS .tmp_vmlinux.kallsyms3.S > > > > > AS .tmp_vmlinux.kallsyms3.S > > > > > LD vmlinux > > > > > BTFIDS vmlinux > > > > > FAILED: load BTF from vmlinux: No such file or directory > > > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > > > > make[1]: *** Deleting file 'vmlinux' > > > > > make: *** [Makefile:1264: vmlinux] Error 2 > > > > I can't reproduce that.. I tried with gcc versions: > > > > > > > > gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) > > > > gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) > > > > > > > > I haven't found fedora setup with 12.2.1 20230111 yet > > > > > > > > I tried alsa with latest pahole master branch > > > > > > > > were you guys able to get any more verbose output > > > > that I suggested earlier? > > > > > > > > jirka > > > I compiled with and without IBT using the -V on pahole (LLVM_OBJCOPY=objcopy pahole -V -J --btf_gen_floats -j .tmp_vmlinux.btf) and the outfiles are a little too big (540MB). The error happens with this CONST type pointing to itself. That does not happen with the IBT option removed. > > > > > > $ grep -n "CONST (anon) type_id" /tmp/with_IBT | more > > > 346:[2] CONST (anon) type_id=2 > > > 349:[5] CONST (anon) type_id=5 > > > 351:[7] CONST (anon) type_id=7 > > > 356:[12] CONST (anon) type_id=12 > > > 363:[19] CONST (anon) type_id=19 > > > 373:[29] CONST (anon) type_id=29 > > > 375:[31] CONST (anon) type_id=31 > > > 409:[63] CONST (anon) type_id=63 > > > 444:[89] CONST (anon) type_id=0 > > > 472:[97] CONST (anon) type_id=97 > > > 616:[129] CONST (anon) type_id=129 > > > 652:[131] CONST (anon) type_id=131 > > > 1319:[234] CONST (anon) type_id=234 > > > 1372:[246] CONST (anon) type_id=246 > > > .... > > > > > > $diff -ru with_IBT without_IBT > > > --- with_IBT 2023-01-31 09:39:24.915912735 -0600 > > > +++ without_IBT 2023-01-31 09:46:23.456005278 -0600 > > > @@ -340,346 +340,14800 @@ > > > Found per-CPU symbol 'cpu_tlbstate_shared' at address 0x2c040 > > > Found per-CPU symbol 'mce_poll_banks' at address 0x1ad20 > > > Found 341 per-CPU variables! > > > -Found 61470 functions! > > > +Found 61462 functions! > > > +File .tmp_vmlinux.btf: > > > +[1] FUNC_PROTO (anon) return=0 args=(void) > > > +[2] FUNC verify_cpu type_id=1 > > > +[3] FUNC_PROTO (anon) return=0 args=(void) > > > +[4] FUNC sev_verify_cbit type_id=3 > > > +search cu 'arch/x86/kernel/head_64.S' for percpu global variables. > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > +Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > +Found per-CPU symbol 'last_nmi_rip' at address 0x1a018 > > > +Found per-CPU symbol 'nmi_stats' at address 0x1a030 > > > +Found per-CPU symbol 'swallow_nmi' at address 0x1a020 > > > +Found per-CPU symbol 'nmi_state' at address 0x1a010 > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > +Found per-CPU symbol 'nmi_cr2' at address 0x1a008 > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > ... > > > > > > And the lines 342-365 of the with_IBT result: > > > 342 Found 341 per-CPU variables! > > > 343 Found 61470 functions! > > > 344 File .tmp_vmlinux.btf: > > > 345 [1] INT long unsigned int size=8 nr_bits=64 encoding=(none) > > > 346 [2] CONST (anon) type_id=2 > > > 347 [3] PTR (anon) type_id=6 > > > 348 [4] INT char size=1 nr_bits=8 encoding=(none) > > > 349 [5] CONST (anon) type_id=5 > > > 350 [6] INT unsigned int size=4 nr_bits=32 encoding=(none) > > > 351 [7] CONST (anon) type_id=7 > > > 352 [8] TYPEDEF __s8 type_id=10 > > > 353 [9] INT signed char size=1 nr_bits=8 encoding=SIGNED > > > 354 [10] TYPEDEF __u8 type_id=12 > > > 355 [11] INT unsigned char size=1 nr_bits=8 encoding=(none) > > > 356 [12] CONST (anon) type_id=12 > > > 357 [13] TYPEDEF __s16 type_id=15 > > > 358 [14] INT short int size=2 nr_bits=16 encoding=SIGNED > > > 359 [15] TYPEDEF __u16 type_id=17 > > > 360 [16] INT short unsigned int size=2 nr_bits=16 encoding=(none) > > > 361 [17] TYPEDEF __s32 type_id=19 > > > 362 [18] INT int size=4 nr_bits=32 encoding=SIGNED > > > 363 [19] CONST (anon) type_id=19 > > > 364 [20] TYPEDEF __u32 type_id=7 > > > 365 [21] TYPEDEF __s64 type_id=23 > > > > > > lines 342-362 of without_IBT > > > > > > 342 Found 341 per-CPU variables! > > > 343 Found 61462 functions! > > > 344 File .tmp_vmlinux.btf: > > > 345 [1] FUNC_PROTO (anon) return=0 args=(void) > > > 346 [2] FUNC verify_cpu type_id=1 > > > 347 [3] FUNC_PROTO (anon) return=0 args=(void) > > > 348 [4] FUNC sev_verify_cbit type_id=3 > > > 349 search cu 'arch/x86/kernel/head_64.S' for percpu global variables. > > > 350 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > 351 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > 352 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > 353 Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > 354 Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > 355 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > 356 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > 357 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > 358 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > 359 Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 > > > 360 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > 361 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > 362 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > > > If the full debug files are useful or a target grep or diff is better let me know. > > > > > I managed to reproduce this too with IBT enabled; one thing I > > noticed is with pahole built with an up-to-date libbpf and the > > changes in https://github.com/acmel/dwarves/tree/next, the problem > > went away. I didn't have time to root-cause it yet however. > > > > Not sure if you're in a position to do this, but if you can, > > would you mind building pahole from > > > > https://github.com/acmel/dwarves/tree/next > > > > ...and re-testing to see if that helps? Thanks! > > > > Alan > > > Thanks, > > > > I tried with libbpf compiled from master > https://github.com/libbpf/libbpf.git and pahole compiled from next branch on > https://github.com/acmel/dwarve with the same result. > With IBT enabled pahole fails and removing it results in a successful > kernel. hi, in case it slipped, you also need to add new options for pahole: https://lore.kernel.org/bpf/1675949331-27935-1-git-send-email-alan.maguire@oracle.com/ should be added for version 124 for now jirka ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-02-10 14:34 ` Jiri Olsa @ 2023-02-10 15:37 ` Alexandre Ferreira 2023-02-14 6:33 ` Tianyi Liu 0 siblings, 1 reply; 29+ messages in thread From: Alexandre Ferreira @ 2023-02-10 15:37 UTC (permalink / raw) To: Jiri Olsa Cc: Alan Maguire, Daniel Xu, bpf@vger.kernel.org, Arnaldo Carvalho de Melo Jiri, On Fri, Feb 10, 2023 at 8:34 AM Jiri Olsa <olsajiri@gmail.com> wrote: > > On Fri, Feb 10, 2023 at 08:02:23AM -0600, Alexandre Peixoto Ferreira wrote: > > Alam, > > > > On 2/9/23 07:07, Alan Maguire wrote: > > > On 09/02/2023 04:15, Alexandre Peixoto Ferreira wrote: > > > > Jiri, > > > > > > > > On 1/31/23 09:18, Jiri Olsa wrote: > > > > > On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: > > > > > > Jirka and Daniel, > > > > > > > > > > > > On 1/27/23 18:00, Jiri Olsa wrote: > > > > > > > On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: > > > > > > > > On 1/24/23 00:13, Daniel Xu wrote: > > > > > > > > > Hi Jiri, > > > > > > > > > > > > > > > > > > On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: > > > > > > > > > > On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > > > > > > > I'm getting the following error during build: > > > > > > > > > > > > > > > > > > > > > > $ ./tools/testing/selftests/bpf/vmtest.sh -j30 > > > > > > > > > > > [...] > > > > > > > > > > > BTF .btf.vmlinux.bin.o > > > > > > > > > > > btf_encoder__encode: btf__dedup failed! > > > > > > > > > > > Failed to encode BTF > > > > > > > > > > > LD .tmp_vmlinux.kallsyms1 > > > > > > > > > > > NM .tmp_vmlinux.kallsyms1.syms > > > > > > > > > > > KSYMS .tmp_vmlinux.kallsyms1.S > > > > > > > > > > > AS .tmp_vmlinux.kallsyms1.S > > > > > > > > > > > LD .tmp_vmlinux.kallsyms2 > > > > > > > > > > > NM .tmp_vmlinux.kallsyms2.syms > > > > > > > > > > > KSYMS .tmp_vmlinux.kallsyms2.S > > > > > > > > > > > AS .tmp_vmlinux.kallsyms2.S > > > > > > > > > > > LD .tmp_vmlinux.kallsyms3 > > > > > > > > > > > NM .tmp_vmlinux.kallsyms3.syms > > > > > > > > > > > KSYMS .tmp_vmlinux.kallsyms3.S > > > > > > > > > > > AS .tmp_vmlinux.kallsyms3.S > > > > > > > > > > > LD vmlinux > > > > > > > > > > > BTFIDS vmlinux > > > > > > > > > > > FAILED: load BTF from vmlinux: No such file or directory > > > > > > > > > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > > > > > > > > > > make[1]: *** Deleting file 'vmlinux' > > > > > > > > > > > make: *** [Makefile:1264: vmlinux] Error 2 > > > > > > > > > > > > > > > > > > > > > > This happens on both bpf-next/master (84150795a49) and 6.2-rc5 > > > > > > > > > > > (2241ab53cb). > > > > > > > > > > > > > > > > > > > > > > I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as > > > > > > > > > > > upstream pahole on master (02d67c5176) and upstream pahole on > > > > > > > > > > > next (2ca56f4c6f659). > > > > > > > > > > > > > > > > > > > > > > Of the above 6 combinations, I think I've tried all of them (maybe > > > > > > > > > > > missing 1 or 2). > > > > > > > > > > > > > > > > > > > > > > Looks like GCC got updated recently on my machine, so perhaps > > > > > > > > > > > it's related? > > > > > > > > > > > > > > > > > > > > > > CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" > > > > > > > > > > > > > > > > > > > > > > I'll try some debugging, but just wanted to report it first. > > > > > > > > > > hi, > > > > > > > > > > I can't reproduce that.. can you reproduce it outside vmtest.sh? > > > > > > > > > > > > > > > > > > > > there will be lot of output with patch below, but could contain > > > > > > > > > > some more error output > > > > > > > > > Thanks for the hints. Doing a regular build outside of vmtest.sh > > > > > > > > > seems to work ok. So maybe it's a difference in the build config. > > > > > > > > > > > > > > > > > > I'll put a little more time into debugging to see if it goes anywhere. > > > > > > > > > But I'll have to get back to the regularly scheduled programming > > > > > > > > > soon. > > > > > > > > 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails > > > > > > > > in pahole when CONFIG_X86_KERNEL_IBT is set. > > > > > > > could you plese attach your config and the build error? > > > > > > > I can't reproduce that > > > > > > > > > > > > > > thanks, > > > > > > > jirka > > > > > > My working .config is available at https://pastebin.pl/view/bef3765c > > > > > > change CONFIG_X86_KERNEL_IBT to y to get the error. > > > > > > > > > > > > The error is similar to Daniel's and is shown below: > > > > > > > > > > > > LD .tmp_vmlinux.btf > > > > > > BTF .btf.vmlinux.bin.o > > > > > > btf_encoder__encode: btf__dedup failed! > > > > > > Failed to encode BTF > > > > > > LD .tmp_vmlinux.kallsyms1 > > > > > > NM .tmp_vmlinux.kallsyms1.syms > > > > > > KSYMS .tmp_vmlinux.kallsyms1.S > > > > > > AS .tmp_vmlinux.kallsyms1.S > > > > > > LD .tmp_vmlinux.kallsyms2 > > > > > > NM .tmp_vmlinux.kallsyms2.syms > > > > > > KSYMS .tmp_vmlinux.kallsyms2.S > > > > > > AS .tmp_vmlinux.kallsyms2.S > > > > > > LD .tmp_vmlinux.kallsyms3 > > > > > > NM .tmp_vmlinux.kallsyms3.syms > > > > > > KSYMS .tmp_vmlinux.kallsyms3.S > > > > > > AS .tmp_vmlinux.kallsyms3.S > > > > > > LD vmlinux > > > > > > BTFIDS vmlinux > > > > > > FAILED: load BTF from vmlinux: No such file or directory > > > > > > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > > > > > make[1]: *** Deleting file 'vmlinux' > > > > > > make: *** [Makefile:1264: vmlinux] Error 2 > > > > > I can't reproduce that.. I tried with gcc versions: > > > > > > > > > > gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) > > > > > gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) > > > > > > > > > > I haven't found fedora setup with 12.2.1 20230111 yet > > > > > > > > > > I tried alsa with latest pahole master branch > > > > > > > > > > were you guys able to get any more verbose output > > > > > that I suggested earlier? > > > > > > > > > > jirka > > > > I compiled with and without IBT using the -V on pahole (LLVM_OBJCOPY=objcopy pahole -V -J --btf_gen_floats -j .tmp_vmlinux.btf) and the outfiles are a little too big (540MB). The error happens with this CONST type pointing to itself. That does not happen with the IBT option removed. > > > > > > > > $ grep -n "CONST (anon) type_id" /tmp/with_IBT | more > > > > 346:[2] CONST (anon) type_id=2 > > > > 349:[5] CONST (anon) type_id=5 > > > > 351:[7] CONST (anon) type_id=7 > > > > 356:[12] CONST (anon) type_id=12 > > > > 363:[19] CONST (anon) type_id=19 > > > > 373:[29] CONST (anon) type_id=29 > > > > 375:[31] CONST (anon) type_id=31 > > > > 409:[63] CONST (anon) type_id=63 > > > > 444:[89] CONST (anon) type_id=0 > > > > 472:[97] CONST (anon) type_id=97 > > > > 616:[129] CONST (anon) type_id=129 > > > > 652:[131] CONST (anon) type_id=131 > > > > 1319:[234] CONST (anon) type_id=234 > > > > 1372:[246] CONST (anon) type_id=246 > > > > .... > > > > > > > > $diff -ru with_IBT without_IBT > > > > --- with_IBT 2023-01-31 09:39:24.915912735 -0600 > > > > +++ without_IBT 2023-01-31 09:46:23.456005278 -0600 > > > > @@ -340,346 +340,14800 @@ > > > > Found per-CPU symbol 'cpu_tlbstate_shared' at address 0x2c040 > > > > Found per-CPU symbol 'mce_poll_banks' at address 0x1ad20 > > > > Found 341 per-CPU variables! > > > > -Found 61470 functions! > > > > +Found 61462 functions! > > > > +File .tmp_vmlinux.btf: > > > > +[1] FUNC_PROTO (anon) return=0 args=(void) > > > > +[2] FUNC verify_cpu type_id=1 > > > > +[3] FUNC_PROTO (anon) return=0 args=(void) > > > > +[4] FUNC sev_verify_cbit type_id=3 > > > > +search cu 'arch/x86/kernel/head_64.S' for percpu global variables. > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > +Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > > +Found per-CPU symbol 'last_nmi_rip' at address 0x1a018 > > > > +Found per-CPU symbol 'nmi_stats' at address 0x1a030 > > > > +Found per-CPU symbol 'swallow_nmi' at address 0x1a020 > > > > +Found per-CPU symbol 'nmi_state' at address 0x1a010 > > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > +Found per-CPU symbol 'nmi_cr2' at address 0x1a008 > > > > +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > > +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > > +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > ... > > > > > > > > And the lines 342-365 of the with_IBT result: > > > > 342 Found 341 per-CPU variables! > > > > 343 Found 61470 functions! > > > > 344 File .tmp_vmlinux.btf: > > > > 345 [1] INT long unsigned int size=8 nr_bits=64 encoding=(none) > > > > 346 [2] CONST (anon) type_id=2 > > > > 347 [3] PTR (anon) type_id=6 > > > > 348 [4] INT char size=1 nr_bits=8 encoding=(none) > > > > 349 [5] CONST (anon) type_id=5 > > > > 350 [6] INT unsigned int size=4 nr_bits=32 encoding=(none) > > > > 351 [7] CONST (anon) type_id=7 > > > > 352 [8] TYPEDEF __s8 type_id=10 > > > > 353 [9] INT signed char size=1 nr_bits=8 encoding=SIGNED > > > > 354 [10] TYPEDEF __u8 type_id=12 > > > > 355 [11] INT unsigned char size=1 nr_bits=8 encoding=(none) > > > > 356 [12] CONST (anon) type_id=12 > > > > 357 [13] TYPEDEF __s16 type_id=15 > > > > 358 [14] INT short int size=2 nr_bits=16 encoding=SIGNED > > > > 359 [15] TYPEDEF __u16 type_id=17 > > > > 360 [16] INT short unsigned int size=2 nr_bits=16 encoding=(none) > > > > 361 [17] TYPEDEF __s32 type_id=19 > > > > 362 [18] INT int size=4 nr_bits=32 encoding=SIGNED > > > > 363 [19] CONST (anon) type_id=19 > > > > 364 [20] TYPEDEF __u32 type_id=7 > > > > 365 [21] TYPEDEF __s64 type_id=23 > > > > > > > > lines 342-362 of without_IBT > > > > > > > > 342 Found 341 per-CPU variables! > > > > 343 Found 61462 functions! > > > > 344 File .tmp_vmlinux.btf: > > > > 345 [1] FUNC_PROTO (anon) return=0 args=(void) > > > > 346 [2] FUNC verify_cpu type_id=1 > > > > 347 [3] FUNC_PROTO (anon) return=0 args=(void) > > > > 348 [4] FUNC sev_verify_cbit type_id=3 > > > > 349 search cu 'arch/x86/kernel/head_64.S' for percpu global variables. > > > > 350 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > 351 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > 352 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > 353 Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 > > > > 354 Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 > > > > 355 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > 356 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > 357 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > 358 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 > > > > 359 Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 > > > > 360 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > 361 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 > > > > 362 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 > > > > > > > > If the full debug files are useful or a target grep or diff is better let me know. > > > > > > > I managed to reproduce this too with IBT enabled; one thing I > > > noticed is with pahole built with an up-to-date libbpf and the > > > changes in https://github.com/acmel/dwarves/tree/next, the problem > > > went away. I didn't have time to root-cause it yet however. > > > > > > Not sure if you're in a position to do this, but if you can, > > > would you mind building pahole from > > > > > > https://github.com/acmel/dwarves/tree/next > > > > > > ...and re-testing to see if that helps? Thanks! > > > > > > Alan > > > > Thanks, > > > > > > I tried with libbpf compiled from master > > https://github.com/libbpf/libbpf.git and pahole compiled from next branch on > > https://github.com/acmel/dwarve with the same result. > > With IBT enabled pahole fails and removing it results in a successful > > kernel. > > hi, > in case it slipped, you also need to add new options for pahole: > https://lore.kernel.org/bpf/1675949331-27935-1-git-send-email-alan.maguire@oracle.com/ > > should be added for version 124 for now > > jirka Added the patch to include options on pahole but same problem. $ pahole --version v1.25 $ ls -l /usr/lib64/libbpf.so.1.2.0 -rwxr-xr-x 1 root root 422088 Feb 9 13:23 /usr/lib64/libbpf.so.1.2.0 UPD include/generated/utsversion.h CC init/version-timestamp.o LD .tmp_vmlinux.btf BTF .btf.vmlinux.bin.o LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j --skip_encoding_btf_inconsistent_proto --btf_gen_optimized .tmp_vmlinux.btf btf_encoder__encode: btf__dedup failed! Failed to encode BTF Thanks, ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' 2023-02-10 15:37 ` Alexandre Ferreira @ 2023-02-14 6:33 ` Tianyi Liu 2023-04-11 17:00 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Josh Poimboeuf 0 siblings, 1 reply; 29+ messages in thread From: Tianyi Liu @ 2023-02-14 6:33 UTC (permalink / raw) To: alexandref75, olsajiri; +Cc: acme, alan.maguire, bpf, dxu, yhs, Tianyi Liu Hi Alex and Jiri, On 2023/2/10 23:37, Alexandre Ferreira wrote: > Jiri, > > On Fri, Feb 10, 2023 at 8:34 AM Jiri Olsa <olsajiri@gmail.com> wrote: >> On Fri, Feb 10, 2023 at 08:02:23AM -0600, Alexandre Peixoto Ferreira wrote: >>> Alam, >>> >>> On 2/9/23 07:07, Alan Maguire wrote: >>>> On 09/02/2023 04:15, Alexandre Peixoto Ferreira wrote: >>>>> Jiri, >>>>> >>>>> On 1/31/23 09:18, Jiri Olsa wrote: >>>>>> On Sat, Jan 28, 2023 at 01:23:25PM -0600, Alexandre Peixoto Ferreira wrote: >>>>>>> Jirka and Daniel, >>>>>>> >>>>>>> On 1/27/23 18:00, Jiri Olsa wrote: >>>>>>>> On Fri, Jan 27, 2023 at 04:28:54PM -0600, Alexandre Peixoto Ferreira wrote: >>>>>>>>> On 1/24/23 00:13, Daniel Xu wrote: >>>>>>>>>> Hi Jiri, >>>>>>>>>> >>>>>>>>>> On Mon, Jan 23, 2023, at 1:06 AM, Jiri Olsa wrote: >>>>>>>>>>> On Sun, Jan 22, 2023 at 10:48:44AM -0700, Daniel Xu wrote: >>>>>>>>>>>> Hi, >>>>>>>>>>>> >>>>>>>>>>>> I'm getting the following error during build: >>>>>>>>>>>> >>>>>>>>>>>> $ ./tools/testing/selftests/bpf/vmtest.sh -j30 >>>>>>>>>>>> [...] >>>>>>>>>>>> BTF .btf.vmlinux.bin.o >>>>>>>>>>>> btf_encoder__encode: btf__dedup failed! >>>>>>>>>>>> Failed to encode BTF >>>>>>>>>>>> LD .tmp_vmlinux.kallsyms1 >>>>>>>>>>>> NM .tmp_vmlinux.kallsyms1.syms >>>>>>>>>>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>>>>>>>>>> AS .tmp_vmlinux.kallsyms1.S >>>>>>>>>>>> LD .tmp_vmlinux.kallsyms2 >>>>>>>>>>>> NM .tmp_vmlinux.kallsyms2.syms >>>>>>>>>>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>>>>>>>>>> AS .tmp_vmlinux.kallsyms2.S >>>>>>>>>>>> LD .tmp_vmlinux.kallsyms3 >>>>>>>>>>>> NM .tmp_vmlinux.kallsyms3.syms >>>>>>>>>>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>>>>>>>>>> AS .tmp_vmlinux.kallsyms3.S >>>>>>>>>>>> LD vmlinux >>>>>>>>>>>> BTFIDS vmlinux >>>>>>>>>>>> FAILED: load BTF from vmlinux: No such file or directory >>>>>>>>>>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>>>>>>>>>> make[1]: *** Deleting file 'vmlinux' >>>>>>>>>>>> make: *** [Makefile:1264: vmlinux] Error 2 >>>>>>>>>>>> >>>>>>>>>>>> This happens on both bpf-next/master (84150795a49) and 6.2-rc5 >>>>>>>>>>>> (2241ab53cb). >>>>>>>>>>>> >>>>>>>>>>>> I've also tried arch linux pahole 1:1.24+r29+g02d67c5-1 as well as >>>>>>>>>>>> upstream pahole on master (02d67c5176) and upstream pahole on >>>>>>>>>>>> next (2ca56f4c6f659). >>>>>>>>>>>> >>>>>>>>>>>> Of the above 6 combinations, I think I've tried all of them (maybe >>>>>>>>>>>> missing 1 or 2). >>>>>>>>>>>> >>>>>>>>>>>> Looks like GCC got updated recently on my machine, so perhaps >>>>>>>>>>>> it's related? >>>>>>>>>>>> >>>>>>>>>>>> CONFIG_CC_VERSION_TEXT="gcc (GCC) 12.2.1 20230111" >>>>>>>>>>>> >>>>>>>>>>>> I'll try some debugging, but just wanted to report it first. >>>>>>>>>>> hi, >>>>>>>>>>> I can't reproduce that.. can you reproduce it outside vmtest.sh? >>>>>>>>>>> >>>>>>>>>>> there will be lot of output with patch below, but could contain >>>>>>>>>>> some more error output >>>>>>>>>> Thanks for the hints. Doing a regular build outside of vmtest.sh >>>>>>>>>> seems to work ok. So maybe it's a difference in the build config. >>>>>>>>>> >>>>>>>>>> I'll put a little more time into debugging to see if it goes anywhere. >>>>>>>>>> But I'll have to get back to the regularly scheduled programming >>>>>>>>>> soon. >>>>>>>>> 6.2-rc5 compiles correctly when CONFIG_X86_KERNEL_IBT is commented but fails >>>>>>>>> in pahole when CONFIG_X86_KERNEL_IBT is set. >>>>>>>> could you plese attach your config and the build error? >>>>>>>> I can't reproduce that >>>>>>>> >>>>>>>> thanks, >>>>>>>> jirka >>>>>>> My working .config is available at https://pastebin.pl/view/bef3765c >>>>>>> change CONFIG_X86_KERNEL_IBT to y to get the error. >>>>>>> >>>>>>> The error is similar to Daniel's and is shown below: >>>>>>> >>>>>>> LD .tmp_vmlinux.btf >>>>>>> BTF .btf.vmlinux.bin.o >>>>>>> btf_encoder__encode: btf__dedup failed! >>>>>>> Failed to encode BTF >>>>>>> LD .tmp_vmlinux.kallsyms1 >>>>>>> NM .tmp_vmlinux.kallsyms1.syms >>>>>>> KSYMS .tmp_vmlinux.kallsyms1.S >>>>>>> AS .tmp_vmlinux.kallsyms1.S >>>>>>> LD .tmp_vmlinux.kallsyms2 >>>>>>> NM .tmp_vmlinux.kallsyms2.syms >>>>>>> KSYMS .tmp_vmlinux.kallsyms2.S >>>>>>> AS .tmp_vmlinux.kallsyms2.S >>>>>>> LD .tmp_vmlinux.kallsyms3 >>>>>>> NM .tmp_vmlinux.kallsyms3.syms >>>>>>> KSYMS .tmp_vmlinux.kallsyms3.S >>>>>>> AS .tmp_vmlinux.kallsyms3.S >>>>>>> LD vmlinux >>>>>>> BTFIDS vmlinux >>>>>>> FAILED: load BTF from vmlinux: No such file or directory >>>>>>> make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 >>>>>>> make[1]: *** Deleting file 'vmlinux' >>>>>>> make: *** [Makefile:1264: vmlinux] Error 2 >>>>>> I can't reproduce that.. I tried with gcc versions: >>>>>> >>>>>> gcc (GCC) 13.0.1 20230117 (Red Hat 13.0.1-0) >>>>>> gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-4) >>>>>> >>>>>> I haven't found fedora setup with 12.2.1 20230111 yet >>>>>> >>>>>> I tried alsa with latest pahole master branch >>>>>> >>>>>> were you guys able to get any more verbose output >>>>>> that I suggested earlier? >>>>>> >>>>>> jirka >>>>> I compiled with and without IBT using the -V on pahole (LLVM_OBJCOPY=objcopy pahole -V -J --btf_gen_floats -j .tmp_vmlinux.btf) and the outfiles are a little too big (540MB). The error happens with this CONST type pointing to itself. That does not happen with the IBT option removed. >>>>> >>>>> $ grep -n "CONST (anon) type_id" /tmp/with_IBT | more >>>>> 346:[2] CONST (anon) type_id=2 >>>>> 349:[5] CONST (anon) type_id=5 >>>>> 351:[7] CONST (anon) type_id=7 >>>>> 356:[12] CONST (anon) type_id=12 >>>>> 363:[19] CONST (anon) type_id=19 >>>>> 373:[29] CONST (anon) type_id=29 >>>>> 375:[31] CONST (anon) type_id=31 >>>>> 409:[63] CONST (anon) type_id=63 >>>>> 444:[89] CONST (anon) type_id=0 >>>>> 472:[97] CONST (anon) type_id=97 >>>>> 616:[129] CONST (anon) type_id=129 >>>>> 652:[131] CONST (anon) type_id=131 >>>>> 1319:[234] CONST (anon) type_id=234 >>>>> 1372:[246] CONST (anon) type_id=246 >>>>> .... >>>>> >>>>> $diff -ru with_IBT without_IBT >>>>> --- with_IBT 2023-01-31 09:39:24.915912735 -0600 >>>>> +++ without_IBT 2023-01-31 09:46:23.456005278 -0600 >>>>> @@ -340,346 +340,14800 @@ >>>>> Found per-CPU symbol 'cpu_tlbstate_shared' at address 0x2c040 >>>>> Found per-CPU symbol 'mce_poll_banks' at address 0x1ad20 >>>>> Found 341 per-CPU variables! >>>>> -Found 61470 functions! >>>>> +Found 61462 functions! >>>>> +File .tmp_vmlinux.btf: >>>>> +[1] FUNC_PROTO (anon) return=0 args=(void) >>>>> +[2] FUNC verify_cpu type_id=1 >>>>> +[3] FUNC_PROTO (anon) return=0 args=(void) >>>>> +[4] FUNC sev_verify_cbit type_id=3 >>>>> +search cu 'arch/x86/kernel/head_64.S' for percpu global variables. >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >>>>> +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> +Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >>>>> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >>>>> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> +Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >>>>> +Found per-CPU symbol 'last_nmi_rip' at address 0x1a018 >>>>> +Found per-CPU symbol 'nmi_stats' at address 0x1a030 >>>>> +Found per-CPU symbol 'swallow_nmi' at address 0x1a020 >>>>> +Found per-CPU symbol 'nmi_state' at address 0x1a010 >>>>> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> +Found per-CPU symbol 'nmi_cr2' at address 0x1a008 >>>>> +Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> +Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >>>>> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >>>>> +Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >>>>> +Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> ... >>>>> >>>>> And the lines 342-365 of the with_IBT result: >>>>> 342 Found 341 per-CPU variables! >>>>> 343 Found 61470 functions! >>>>> 344 File .tmp_vmlinux.btf: >>>>> 345 [1] INT long unsigned int size=8 nr_bits=64 encoding=(none) >>>>> 346 [2] CONST (anon) type_id=2 >>>>> 347 [3] PTR (anon) type_id=6 >>>>> 348 [4] INT char size=1 nr_bits=8 encoding=(none) >>>>> 349 [5] CONST (anon) type_id=5 >>>>> 350 [6] INT unsigned int size=4 nr_bits=32 encoding=(none) >>>>> 351 [7] CONST (anon) type_id=7 >>>>> 352 [8] TYPEDEF __s8 type_id=10 >>>>> 353 [9] INT signed char size=1 nr_bits=8 encoding=SIGNED >>>>> 354 [10] TYPEDEF __u8 type_id=12 >>>>> 355 [11] INT unsigned char size=1 nr_bits=8 encoding=(none) >>>>> 356 [12] CONST (anon) type_id=12 >>>>> 357 [13] TYPEDEF __s16 type_id=15 >>>>> 358 [14] INT short int size=2 nr_bits=16 encoding=SIGNED >>>>> 359 [15] TYPEDEF __u16 type_id=17 >>>>> 360 [16] INT short unsigned int size=2 nr_bits=16 encoding=(none) >>>>> 361 [17] TYPEDEF __s32 type_id=19 >>>>> 362 [18] INT int size=4 nr_bits=32 encoding=SIGNED >>>>> 363 [19] CONST (anon) type_id=19 >>>>> 364 [20] TYPEDEF __u32 type_id=7 >>>>> 365 [21] TYPEDEF __s64 type_id=23 >>>>> >>>>> lines 342-362 of without_IBT >>>>> >>>>> 342 Found 341 per-CPU variables! >>>>> 343 Found 61462 functions! >>>>> 344 File .tmp_vmlinux.btf: >>>>> 345 [1] FUNC_PROTO (anon) return=0 args=(void) >>>>> 346 [2] FUNC verify_cpu type_id=1 >>>>> 347 [3] FUNC_PROTO (anon) return=0 args=(void) >>>>> 348 [4] FUNC sev_verify_cbit type_id=3 >>>>> 349 search cu 'arch/x86/kernel/head_64.S' for percpu global variables. >>>>> 350 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> 351 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> 352 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> 353 Found per-CPU symbol 'cpu_kick_mask' at address 0x19f78 >>>>> 354 Found per-CPU symbol 'cpu_tsc_khz' at address 0x19f88 >>>>> 355 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> 356 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> 357 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> 358 Found per-CPU symbol 'perf_nmi_tstamp' at address 0x19f70 >>>>> 359 Found per-CPU symbol 'current_tsc_ratio' at address 0x19fa0 >>>>> 360 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> 361 Found per-CPU symbol 'cpu_loops_per_jiffy' at address 0x18a08 >>>>> 362 Found per-CPU symbol 'kvm_running_vcpu' at address 0x19f80 >>>>> >>>>> If the full debug files are useful or a target grep or diff is better let me know. >>>>> >>>> I managed to reproduce this too with IBT enabled; one thing I >>>> noticed is with pahole built with an up-to-date libbpf and the >>>> changes in https://github.com/acmel/dwarves/tree/next, the problem >>>> went away. I didn't have time to root-cause it yet however. >>>> >>>> Not sure if you're in a position to do this, but if you can, >>>> would you mind building pahole from >>>> >>>> https://github.com/acmel/dwarves/tree/next >>>> >>>> ...and re-testing to see if that helps? Thanks! >>>> >>>> Alan >>>>> Thanks, >>>>> >>> I tried with libbpf compiled from master >>> https://github.com/libbpf/libbpf.git and pahole compiled from next branch on >>> https://github.com/acmel/dwarve with the same result. >>> With IBT enabled pahole fails and removing it results in a successful >>> kernel. >> hi, >> in case it slipped, you also need to add new options for pahole: >> https://lore.kernel.org/bpf/1675949331-27935-1-git-send-email-alan.maguire@oracle.com/ >> >> should be added for version 124 for now >> >> jirka > > Added the patch to include options on pahole but same problem. > $ pahole --version > v1.25 > $ ls -l /usr/lib64/libbpf.so.1.2.0 > -rwxr-xr-x 1 root root 422088 Feb 9 13:23 /usr/lib64/libbpf.so.1.2.0 > > UPD include/generated/utsversion.h > CC init/version-timestamp.o > LD .tmp_vmlinux.btf > BTF .btf.vmlinux.bin.o > LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j > --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > .tmp_vmlinux.btf > btf_encoder__encode: btf__dedup failed! > Failed to encode BTF > > Thanks, > I encountered the same problem when building a new kernel and I found some reasons for the error. In short, enabling CONFIG_X86_KERNEL_IBT will change the order of records in .notes section. In addition, due to historical problems, the alignment of records in the .notes section is not unified, which leads to the inability of gelf_getnote() to read the records after the wrong one. For example: $readelf -n linux-6.2-rc7-with-IBT/.tmp_vmlinux.btf Displaying notes found in: .notes Owner Data size Description GNU 0x00000020 NT_GNU_PROPERTY_TYPE_0 Properties: x86 feature used: x86, x87, MMX, XMM, FXSR, XSAVE x86 ISA used: x86-64-baseline, x86-64-v2, x86-64-v3 Linux 0x00000004 func description data: 06 00 00 00 readelf: Warning: note with invalid namesz and/or descsz found at offset 0x50 readelf: Warning: type: 0x78, namesize: 0x100, descsize: 0x756e694c, alignment: 8 $readelf -n linux-6.2-rc7-no-IBT/.tmp_vmlinux.btf Displaying notes found in: .notes Owner Data size Description GNU 0x00000020 NT_GNU_PROPERTY_TYPE_0 Properties: x86 feature used: x86, x87, MMX, XMM, FXSR, XSAVE x86 ISA used: x86-64-baseline, x86-64-v2, x86-64-v3 GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring) Build ID: 073b8e5b0373cdc806fac20a9559461be75570a8 readelf: Warning: note with invalid namesz and/or descsz found at offset 0x58 readelf: Warning: type: 0x756e694c, namesize: 0x4, descsize: 0x101, alignment: 8 As shown above, whether IBT is enabled or not, readelf can't read all records in the .notes section. And gelf_getnote() has the same behaviour. In dwarf_loader.c:3001, cus__merging_cu() determines whether cu(compile unit) should be merged by detecting the value of LINUX_ELFNOTE_LTO_INFO. It is from https://github.com/torvalds/linux/blob/master/include/linux/elfnote-lto.h#L9, and its value must be 0 or 1. But in the above output from readelf, it reads "06 00 00 00"(=6), which is impossible. This confirms that the .notes record has format compatibility problems. There's also something similar at https://lore.kernel.org/linux-arm-kernel/20210428172847.GC4022@arm.com/ dwarf_loader.c:3001 uses "!= 0" for judgement. So with IBT=y, gelf_getnote() reads "0x6" and return "true"; while gelf_getnote() crushed before reading the LINUX_ELFNOTE_LTO_INFO with IBT=n, and returns the right result("false") coincidently. Since the kernel is not built with CONFIG_LTO, merging compile units will lead to undefined behaviors. Specifically, there are tags such as DW_TAG_unspecified_type in the origin cus, but were filtered out in BTF encders. This causes the small_id(dwarf reader assigned) is malposed with the offset(which btf encoder uses), and finally leads to the "btf__dedup failed!" error. There's an simple fix for pahole. To some extent, this prevents cus__merging_cu() from being disturbed by alignment errors, but the fundamental solution is to fix the alignment problem of .notes section. Signed-off-by: Tianyi Liu <i.pear@outlook.com> --- dwarf_loader.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/dwarf_loader.c b/dwarf_loader.c index a77598d..b2e9863 100644 --- a/dwarf_loader.c +++ b/dwarf_loader.c @@ -2998,7 +2998,7 @@ static bool cus__merging_cu(Dwarf *dw, Elf *elf) if (strcmp((char *)data->d_buf + name_off, "Linux") != 0) continue; - return *(int *)(data->d_buf + desc_off) != 0; + return *(int *)(data->d_buf + desc_off) == 1; } } } -- 2.39.1 ^ permalink raw reply related [flat|nested] 29+ messages in thread
* [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-02-14 6:33 ` Tianyi Liu @ 2023-04-11 17:00 ` Josh Poimboeuf 2023-04-12 7:10 ` Tianyi Liu 0 siblings, 1 reply; 29+ messages in thread From: Josh Poimboeuf @ 2023-04-11 17:00 UTC (permalink / raw) To: Tianyi Liu Cc: alexandref75, olsajiri, acme, alan.maguire, bpf, dxu, yhs, Peter Zijlstra, linux-kernel, ptalbert, jforbes On Tue, Feb 14, 2023 at 02:33:02PM +0800, Tianyi Liu wrote: > > LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j > > --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > > .tmp_vmlinux.btf > > btf_encoder__encode: btf__dedup failed! > > Failed to encode BTF > > > > Thanks, > > > > I encountered the same problem when building a new kernel and I found some > reasons for the error. > > In short, enabling CONFIG_X86_KERNEL_IBT will change the order of records in > .notes section. In addition, due to historical problems, the alignment of > records in the .notes section is not unified, which leads to the inability of > gelf_getnote() to read the records after the wrong one. Alexandre, Tianyi, are you still seeing this issue with the latest dwarves? If so can you confirm the below patch fixes it? Apparently the latest dwarves release fixes it on Fedora Rawhide [1], does anybody know if there a specific dwarves and/or libbpf change for this? [1] https://gitlab.com/cki-project/kernel-ark/-/merge_requests/2346#note_1348057786 ---8<--- From: Josh Poimboeuf <jpoimboe@kernel.org> Subject: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes When tooling reads ELF notes, it assumes each note entry is aligned to the value listed in the .note section header's sh_addralign field. The kernel-created ELF notes in the .note.Linux and .note.Xen sections are aligned to 4 bytes. This causes the toolchain to set those sections' sh_addralign values to 4. On the other hand, the GCC-created .note.gnu.property section has an sh_addralign value of 8 for some reason, despite being based on struct Elf32_Nhdr which only needs 4-byte alignment. When the mismatched input sections get linked together into the vmlinux .notes output section, the higher alignment "wins", resulting in an sh_addralign of 8, which confuses tooling. For example: $ readelf -n .tmp_vmlinux.btf ... readelf: .tmp_vmlinux.btf: Warning: note with invalid namesz and/or descsz found at offset 0x170 readelf: .tmp_vmlinux.btf: Warning: type: 0x4, namesize: 0x006e6558, descsize: 0x00008801, alignment: 8 In this case readelf thinks there's alignment padding where there is none, so it starts reading an ELF note in the middle. With newer toolchains (e.g., latest Fedora Rawhide), a similar mismatch triggers a build failure when combined with CONFIG_X86_KERNEL_IBT: btf_encoder__encode: btf__dedup failed! Failed to encode BTF libbpf: failed to find '.BTF' ELF section in vmlinux FAILED: load BTF from vmlinux: No data available make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 Fix it by forcing the .notes section input and output alignments to 4 to match the kernel's note entry alignments. Note this doesn't break the 8-byte-aligned .note.gnu.property entries because their internal data representations fill the entire 8-byte alignment boundary, so there's no padding between entries to be misinterpreted. And there's only a single entry in that section anyway. Reported-by: Daniel Xu <dxu@dxuuu.xyz> Debugged-by: Tianyi Liu <i.pear@outlook.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- include/asm-generic/vmlinux.lds.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..1c7c87c9ae71 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -894,7 +894,7 @@ */ #define NOTES \ /DISCARD/ : { *(.note.GNU-stack) } \ - .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \ + .notes ALIGN(4) : AT(ADDR(.notes) - LOAD_OFFSET) SUBALIGN(4) { \ BOUNDED_SECTION_BY(.note.*, _notes) \ } NOTES_HEADERS \ NOTES_HEADERS_RESTORE -- 2.39.2 ^ permalink raw reply related [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-11 17:00 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Josh Poimboeuf @ 2023-04-12 7:10 ` Tianyi Liu 2023-04-12 16:30 ` Josh Poimboeuf 0 siblings, 1 reply; 29+ messages in thread From: Tianyi Liu @ 2023-04-12 7:10 UTC (permalink / raw) To: jpoimboe Cc: acme, alan.maguire, alexandref75, bpf, dxu, i.pear, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs On Tue, Apr 11, 2023 at 17:00 , Josh Poimboeuf wrote: > On Tue, Feb 14, 2023 at 02:33:02PM +0800, Tianyi Liu wrote: > > > LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j > > > --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > > > .tmp_vmlinux.btf > > > btf_encoder__encode: btf__dedup failed! > > > Failed to encode BTF > > > > > > Thanks, > > > > > > > I encountered the same problem when building a new kernel and I found some > > reasons for the error. > > > > In short, enabling CONFIG_X86_KERNEL_IBT will change the order of records in > > .notes section. In addition, due to historical problems, the alignment of > > records in the .notes section is not unified, which leads to the inability of > > gelf_getnote() to read the records after the wrong one. > > Alexandre, Tianyi, are you still seeing this issue with the latest > dwarves? If so can you confirm the below patch fixes it? > Josh, first of all, thank you very much for your help. However, this patch doesn't work in my environment. I am using gcc 12.2.1 20230201. After compiling, when I use readelf -S to view ELF sections, the align of .notes section is still 8: $ readelf -S .tmp_vmlinux.btf [20] .notes NOTE ffffffff8250b570 0170b570 0000000000000084 0000000000000000 A 0 0 8 > Apparently the latest dwarves release fixes it on Fedora Rawhide [1], > does anybody know if there a specific dwarves and/or libbpf change for > this? > It has been fixed in dwarves[1], but it may just be a coincidence. > [1] https://gitlab.com/cki-project/kernel-ark/-/merge_requests/2346#note_1348057786 > > ---8<--- > > From: Josh Poimboeuf <jpoimboe@kernel.org> > Subject: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes > > When tooling reads ELF notes, it assumes each note entry is aligned to > the value listed in the .note section header's sh_addralign field. > > The kernel-created ELF notes in the .note.Linux and .note.Xen sections > are aligned to 4 bytes. This causes the toolchain to set those > sections' sh_addralign values to 4. > > On the other hand, the GCC-created .note.gnu.property section has an > sh_addralign value of 8 for some reason, despite being based on struct > Elf32_Nhdr which only needs 4-byte alignment. > > When the mismatched input sections get linked together into the vmlinux > .notes output section, the higher alignment "wins", resulting in an > sh_addralign of 8, which confuses tooling. For example: > > $ readelf -n .tmp_vmlinux.btf > ... > readelf: .tmp_vmlinux.btf: Warning: note with invalid namesz and/or descsz found at offset 0x170 > readelf: .tmp_vmlinux.btf: Warning: type: 0x4, namesize: 0x006e6558, descsize: 0x00008801, alignment: 8 > > In this case readelf thinks there's alignment padding where there is > none, so it starts reading an ELF note in the middle. > > With newer toolchains (e.g., latest Fedora Rawhide), a similar mismatch > triggers a build failure when combined with CONFIG_X86_KERNEL_IBT: > > btf_encoder__encode: btf__dedup failed! > Failed to encode BTF > libbpf: failed to find '.BTF' ELF section in vmlinux > FAILED: load BTF from vmlinux: No data available > make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 > > Fix it by forcing the .notes section input and output alignments to 4 to > match the kernel's note entry alignments. > > Note this doesn't break the 8-byte-aligned .note.gnu.property entries > because their internal data representations fill the entire 8-byte > alignment boundary, so there's no padding between entries to be > misinterpreted. And there's only a single entry in that section anyway. > > Reported-by: Daniel Xu <dxu@dxuuu.xyz> > Debugged-by: Tianyi Liu <i.pear@outlook.com> > Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> > --- > include/asm-generic/vmlinux.lds.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index d1f57e4868ed..1c7c87c9ae71 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -894,7 +894,7 @@ > */ > #define NOTES \ > /DISCARD/ : { *(.note.GNU-stack) } \ > - .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \ > + .notes ALIGN(4) : AT(ADDR(.notes) - LOAD_OFFSET) SUBALIGN(4) { \ > BOUNDED_SECTION_BY(.note.*, _notes) \ > } NOTES_HEADERS \ > NOTES_HEADERS_RESTORE > -- > 2.39.2 [1] https://github.com/acmel/dwarves/commit/a9498899109d3be14f17abbc322a8f55a1067bee ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-12 7:10 ` Tianyi Liu @ 2023-04-12 16:30 ` Josh Poimboeuf 2023-04-13 2:21 ` Joan Bruguera Micó 2023-04-13 4:54 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Tianyi Liu 0 siblings, 2 replies; 29+ messages in thread From: Josh Poimboeuf @ 2023-04-12 16:30 UTC (permalink / raw) To: Tianyi Liu Cc: acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs On Wed, Apr 12, 2023 at 03:10:14PM +0800, Tianyi Liu wrote: > On Tue, Apr 11, 2023 at 17:00 , Josh Poimboeuf wrote: > > On Tue, Feb 14, 2023 at 02:33:02PM +0800, Tianyi Liu wrote: > > > > LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j > > > > --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > > > > .tmp_vmlinux.btf > > > > btf_encoder__encode: btf__dedup failed! > > > > Failed to encode BTF > > > > > > > > Thanks, > > > > > > > > > > I encountered the same problem when building a new kernel and I found some > > > reasons for the error. > > > > > > In short, enabling CONFIG_X86_KERNEL_IBT will change the order of records in > > > .notes section. In addition, due to historical problems, the alignment of > > > records in the .notes section is not unified, which leads to the inability of > > > gelf_getnote() to read the records after the wrong one. > > > > Alexandre, Tianyi, are you still seeing this issue with the latest > > dwarves? If so can you confirm the below patch fixes it? > > > > Josh, first of all, thank you very much for your help. However, this patch > doesn't work in my environment. I am using gcc 12.2.1 20230201. > After compiling, when I use readelf -S to view ELF sections, > the align of .notes section is still 8: > > $ readelf -S .tmp_vmlinux.btf > [20] .notes NOTE ffffffff8250b570 0170b570 > 0000000000000084 0000000000000000 A 0 0 8 Hm, weird. > > Apparently the latest dwarves release fixes it on Fedora Rawhide [1], > > does anybody know if there a specific dwarves and/or libbpf change for > > this? > > > > It has been fixed in dwarves[1], but it may just be a coincidence. So just to confirm, the btf__dedup error is gone for you with the latest dwarves? -- Josh ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-12 16:30 ` Josh Poimboeuf @ 2023-04-13 2:21 ` Joan Bruguera Micó 2023-04-13 9:23 ` Tianyi Liu 2023-04-13 4:54 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Tianyi Liu 1 sibling, 1 reply; 29+ messages in thread From: Joan Bruguera Micó @ 2023-04-13 2:21 UTC (permalink / raw) To: jpoimboe Cc: i.pear, acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs I have done some tests with Arch Linux which is also affected by this issue: Base scenario: Running Arch Linux updated as of 2023-04-13. Building the linux-mainline 6.3rc6-1 from AUR (https://aur.archlinux.org/packages/linux-mainline) with CONFIG_X86_KERNEL_IBT changed to 'y' Result: Build fails with the "btf__dedup failed!" error Test 1: Update dwarves (=pahole package on Arch Linux) from the current version (1:1.24+r29+g02d67c5-1) to the staging version (1:1.25-1). Result: The build works correctly. However, the notes section is still not parsed correctly, as confirmed by `readelf -n` or adding a printf near the code on `cus__merging_cu` (on `dwarf_loader.c`) pointed to by Tianyi. A bisect shows the commit that fixes the build is a9498899109d3be14f17abbc322a8f55a1067bee "dwarf_loader: Fix for BTF id drift caused by adding unspecified types" I don't know why though. Test 2: Applying Josh's patch to force-align the ELF notes section to 4 bytes (clarification: using the base pahole version again here) Result: The build works correctly. I can read the notes correctly using `readelf -n` as well, and they are aligned to 4 bytes instead of 8. Test 3: Similar to Josh's patch, but instead of force-aligning the sections, I added `.note.gnu.property` to the `/DISCARD/` list in the line above. Result: The build works correctly. I can read the notes correctly using `readelf -n` as well (of course, the GNU notes which made the alignment be 8 bytes are gone; I don't know if this has any negative effect). So, in summary, either upgrading dwarves/pahole from 1.24 to (not yet fully released?) 1.25, or applying Josh's patch fixes the issue for me. Despite the new dwarves/pahole version fixing the build, Josh's patch or something else to fix the notes alignment is needed. ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-13 2:21 ` Joan Bruguera Micó @ 2023-04-13 9:23 ` Tianyi Liu 2023-04-13 18:59 ` [PATCH] vmlinux.lds.h: Discard .note.gnu.property section Josh Poimboeuf 0 siblings, 1 reply; 29+ messages in thread From: Tianyi Liu @ 2023-04-13 9:23 UTC (permalink / raw) To: joanbrugueram Cc: acme, alan.maguire, alexandref75, bpf, dxu, i.pear, jforbes, jpoimboe, linux-kernel, olsajiri, peterz, ptalbert, yhs On Thu, Apr 13, 2023 at 02:21:49 +0000, Joan Bruguera Micó wrote: > I have done some tests with Arch Linux which is also affected by this issue: > > Base scenario: Running Arch Linux updated as of 2023-04-13. > Building the linux-mainline 6.3rc6-1 from AUR > (https://aur.archlinux.org/packages/linux-mainline) > with CONFIG_X86_KERNEL_IBT changed to 'y' > Result: Build fails with the "btf__dedup failed!" error I use MANJARO with kernel version 6.2.10-1. We should be using the same kernel. > Test 1: Update dwarves (=pahole package on Arch Linux) from the current version > (1:1.24+r29+g02d67c5-1) to the staging version (1:1.25-1). > Result: The build works correctly. > > However, the notes section is still not parsed correctly, as confirmed > by `readelf -n` or adding a printf near the code on `cus__merging_cu` > (on `dwarf_loader.c`) pointed to by Tianyi. > > A bisect shows the commit that fixes the build is > a9498899109d3be14f17abbc322a8f55a1067bee > "dwarf_loader: Fix for BTF id drift caused by adding unspecified types" > I don't know why though. Pahole reads .notes to look for LINUX_ELFNOTE_BUILD_LTO. When LTO is enabled, pahole needs to call cus__merge_and_process_cu to merge compile units, at which point there should only be one unspecified type (used to represent some compilation information) in the global context. However, when the kernel is compiled without LTO, if pahole calls cus__merge_and_process_cu due to alignment issues with notes, multiple unspecified types may appear after merging the cus, and older versions of pahole only support up to one. This is why pahole 1.24 crashes, while newer versions support multiple. However, the latest version of pahole still does not solve the problem of incorrect LTO recognition, so compiling the kernel may be slower than normal. If the only objective is to fix the bug of incorrect LTO recognition, perhaps this naive patch[1] could be sufficient. [1]: https://lore.kernel.org/bpf/SY4P282MB1084A0E31D4228DF89FC42639DA29@SY4P282MB1084.AUSP282.PROD.OUTLOOK.COM/ > Test 2: Applying Josh's patch to force-align the ELF notes section to 4 bytes > (clarification: using the base pahole version again here) > Result: The build works correctly. > I can read the notes correctly using `readelf -n` as well, > and they are aligned to 4 bytes instead of 8. I'm still currently unable to reproduce this fix, but it may just be an issue with my environment. > Test 3: Similar to Josh's patch, but instead of force-aligning the sections, > I added `.note.gnu.property` to the `/DISCARD/` list in the line above. > Result: The build works correctly. > I can read the notes correctly using `readelf -n` as well > (of course, the GNU notes which made the alignment be 8 bytes are gone; > I don't know if this has any negative effect). I think discarding .note.gnu.property will not have side effects. For some reason, this note does not exist in my final vmlinux. I also did not find any usage of this property in the later steps of compiling the kernel. > So, in summary, either upgrading dwarves/pahole from 1.24 to (not yet fully > released?) 1.25, or applying Josh's patch fixes the issue for me. > Despite the new dwarves/pahole version fixing the build, Josh's patch or > something else to fix the notes alignment is needed. ^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH] vmlinux.lds.h: Discard .note.gnu.property section 2023-04-13 9:23 ` Tianyi Liu @ 2023-04-13 18:59 ` Josh Poimboeuf 2023-04-16 19:02 ` Joan Bruguera Micó 0 siblings, 1 reply; 29+ messages in thread From: Josh Poimboeuf @ 2023-04-13 18:59 UTC (permalink / raw) To: Tianyi Liu Cc: joanbrugueram, acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs On Thu, Apr 13, 2023 at 05:23:08PM +0800, Tianyi Liu wrote: > > Test 1: Update dwarves (=pahole package on Arch Linux) from the current version > > (1:1.24+r29+g02d67c5-1) to the staging version (1:1.25-1). > > Result: The build works correctly. > > > > However, the notes section is still not parsed correctly, as confirmed > > by `readelf -n` or adding a printf near the code on `cus__merging_cu` > > (on `dwarf_loader.c`) pointed to by Tianyi. > > > > A bisect shows the commit that fixes the build is > > a9498899109d3be14f17abbc322a8f55a1067bee > > "dwarf_loader: Fix for BTF id drift caused by adding unspecified types" > > I don't know why though. > > Pahole reads .notes to look for LINUX_ELFNOTE_BUILD_LTO. When LTO is > enabled, pahole needs to call cus__merge_and_process_cu to merge compile > units, at which point there should only be one unspecified type (used to > represent some compilation information) in the global context. > > However, when the kernel is compiled without LTO, if pahole calls > cus__merge_and_process_cu due to alignment issues with notes, multiple > unspecified types may appear after merging the cus, and older versions of > pahole only support up to one. This is why pahole 1.24 crashes, while > newer versions support multiple. However, the latest version of pahole > still does not solve the problem of incorrect LTO recognition, so > compiling the kernel may be slower than normal. Thanks for the explanation. So pahole is still mis-reading the LTO note, it just doesn't crash now. > If the only objective is to fix the bug of incorrect LTO recognition, > perhaps this naive patch[1] could be sufficient. > > [1]: https://lore.kernel.org/bpf/SY4P282MB1084A0E31D4228DF89FC42639DA29@SY4P282MB1084.AUSP282.PROD.OUTLOOK.COM/ I think we still need to fix the underlying issue (corrupt .notes section). > > Test 2: Applying Josh's patch to force-align the ELF notes section to 4 bytes > > (clarification: using the base pahole version again here) > > Result: The build works correctly. > > I can read the notes correctly using `readelf -n` as well, > > and they are aligned to 4 bytes instead of 8. > > I'm still currently unable to reproduce this fix, but it may just be an > issue with my environment. > > > Test 3: Similar to Josh's patch, but instead of force-aligning the sections, > > I added `.note.gnu.property` to the `/DISCARD/` list in the line above. > > Result: The build works correctly. > > I can read the notes correctly using `readelf -n` as well > > (of course, the GNU notes which made the alignment be 8 bytes are gone; > > I don't know if this has any negative effect). > > I think discarding .note.gnu.property will not have side effects. For some > reason, this note does not exist in my final vmlinux. I also did not find > any usage of this property in the later steps of compiling the kernel. It looks like CONFIG_DEBUG_INFO_BTF is already (inadvertently) stripping it from vmlinux due to how GNU properties are merged by the linker (see "How GNU properties are merged" in the ld man page). The btf data is extracted from vmlinux.o with "objcopy --only-section=.BTF" into .btf.vmlinux.bin.o. That file doesn't have .note.gnu.property, so when it gets modified and linked back into the main object, the linker strips it. GNU properties are important for user space but they don't seem to have a purpose for vmlinux. So yeah, let's just discard .note.gnu.property. ---8<--- From: Josh Poimboeuf <jpoimboe@kernel.org> Subject: [PATCH] vmlinux.lds.h: Discard .note.gnu.property section When tooling reads ELF notes, it assumes each note entry is aligned to the value listed in the .note section header's sh_addralign field. The kernel-created ELF notes in the .note.Linux and .note.Xen sections are aligned to 4 bytes. This causes the toolchain to set those sections' sh_addralign values to 4. On the other hand, the GCC-created .note.gnu.property section has an sh_addralign value of 8 for some reason, despite being based on struct Elf32_Nhdr which only needs 4-byte alignment. When the mismatched input sections get linked together into the vmlinux .notes output section, the higher alignment "wins", resulting in an sh_addralign of 8, which confuses tooling. For example: $ readelf -n .tmp_vmlinux.btf ... readelf: .tmp_vmlinux.btf: Warning: note with invalid namesz and/or descsz found at offset 0x170 readelf: .tmp_vmlinux.btf: Warning: type: 0x4, namesize: 0x006e6558, descsize: 0x00008801, alignment: 8 In this case readelf thinks there's alignment padding where there is none, so it starts reading an ELF note in the middle. With newer toolchains (e.g., latest Fedora Rawhide), a similar mismatch triggers a build failure when combined with CONFIG_X86_KERNEL_IBT: btf_encoder__encode: btf__dedup failed! Failed to encode BTF libbpf: failed to find '.BTF' ELF section in vmlinux FAILED: load BTF from vmlinux: No data available make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 This latter error was caused by pahole crashing when it encountered the corrupt .notes section. This crash has been fixed in dwarves version 1.25. As Tianyi Liu describes: "Pahole reads .notes to look for LINUX_ELFNOTE_BUILD_LTO. When LTO is enabled, pahole needs to call cus__merge_and_process_cu to merge compile units, at which point there should only be one unspecified type (used to represent some compilation information) in the global context. However, when the kernel is compiled without LTO, if pahole calls cus__merge_and_process_cu due to alignment issues with notes, multiple unspecified types may appear after merging the cus, and older versions of pahole only support up to one. This is why pahole 1.24 crashes, while newer versions support multiple. However, the latest version of pahole still does not solve the problem of incorrect LTO recognition, so compiling the kernel may be slower than normal." Even with the newer pahole, the note section misaligment issue still exists and pahole is misinterpreting the LTO note. Fix it by discarding the .note.gnu.property section. While GNU properties are important for user space (and VDSO), they don't seem to have any use for vmlinux. (In fact, they're already getting (inadvertently) stripped from vmlinux when CONFIG_DEBUG_INFO_BTF is enabled. The BTF data is extracted from vmlinux.o with "objcopy --only-section=.BTF" into .btf.vmlinux.bin.o. That file doesn't have .note.gnu.property, so when it gets modified and linked back into the main object, the linker automatically strips it (see "How GNU properties are merged" in the ld man page).) Reported-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lkml.kernel.org/lkml/57830c30-cd77-40cf-9cd1-3bb608aa602e@app.fastmail.com Debugged-by: Tianyi Liu <i.pear@outlook.com> Suggested-by: Joan Bruguera Micó <joanbrugueram@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- include/asm-generic/vmlinux.lds.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..1770b7d87a80 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -894,6 +894,7 @@ */ #define NOTES \ /DISCARD/ : { *(.note.GNU-stack) } \ + /DISCARD/ : { *(.note.gnu.property) } \ .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \ BOUNDED_SECTION_BY(.note.*, _notes) \ } NOTES_HEADERS \ -- 2.39.2 ^ permalink raw reply related [flat|nested] 29+ messages in thread
* [PATCH] vmlinux.lds.h: Discard .note.gnu.property section 2023-04-13 18:59 ` [PATCH] vmlinux.lds.h: Discard .note.gnu.property section Josh Poimboeuf @ 2023-04-16 19:02 ` Joan Bruguera Micó 2023-04-18 21:47 ` Josh Poimboeuf 0 siblings, 1 reply; 29+ messages in thread From: Joan Bruguera Micó @ 2023-04-16 19:02 UTC (permalink / raw) To: jpoimboe Cc: i.pear, acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs Two small nitpicks: > Link: https://lkml.kernel.org/lkml/57830c30-cd77-40cf-9cd1-3bb608aa602e@app.fastmail.com This link is "semi-broken", it should go to /bpf/ instead of /lkml/. > /DISCARD/ : { *(.note.GNU-stack) } \ > + /DISCARD/ : { *(.note.gnu.property) } \ Both discards can go in the same DISCARD block. (just style; it's how it's most often done in other linker scripts) ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Discard .note.gnu.property section 2023-04-16 19:02 ` Joan Bruguera Micó @ 2023-04-18 21:47 ` Josh Poimboeuf 2023-04-18 21:49 ` [PATCH v2] " Josh Poimboeuf 0 siblings, 1 reply; 29+ messages in thread From: Josh Poimboeuf @ 2023-04-18 21:47 UTC (permalink / raw) To: Joan Bruguera Micó Cc: i.pear, acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs On Sun, Apr 16, 2023 at 07:02:19PM +0000, Joan Bruguera Micó wrote: > Two small nitpicks: > > > Link: https://lkml.kernel.org/lkml/57830c30-cd77-40cf-9cd1-3bb608aa602e@app.fastmail.com > > This link is "semi-broken", it should go to /bpf/ instead of /lkml/. > > > /DISCARD/ : { *(.note.GNU-stack) } \ > > + /DISCARD/ : { *(.note.gnu.property) } \ > > Both discards can go in the same DISCARD block. > (just style; it's how it's most often done in other linker scripts) Thanks. I also noticed the comment above the change needs an update. Posting v2 shortly. -- Josh ^ permalink raw reply [flat|nested] 29+ messages in thread
* [PATCH v2] vmlinux.lds.h: Discard .note.gnu.property section 2023-04-18 21:47 ` Josh Poimboeuf @ 2023-04-18 21:49 ` Josh Poimboeuf 0 siblings, 0 replies; 29+ messages in thread From: Josh Poimboeuf @ 2023-04-18 21:49 UTC (permalink / raw) To: Joan Bruguera Micó Cc: i.pear, acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs When tooling reads ELF notes, it assumes each note entry is aligned to the value listed in the .note section header's sh_addralign field. The kernel-created ELF notes in the .note.Linux and .note.Xen sections are aligned to 4 bytes. This causes the toolchain to set those sections' sh_addralign values to 4. On the other hand, the GCC-created .note.gnu.property section has an sh_addralign value of 8 for some reason, despite being based on struct Elf32_Nhdr which only needs 4-byte alignment. When the mismatched input sections get linked together into the vmlinux .notes output section, the higher alignment "wins", resulting in an sh_addralign of 8, which confuses tooling. For example: $ readelf -n .tmp_vmlinux.btf ... readelf: .tmp_vmlinux.btf: Warning: note with invalid namesz and/or descsz found at offset 0x170 readelf: .tmp_vmlinux.btf: Warning: type: 0x4, namesize: 0x006e6558, descsize: 0x00008801, alignment: 8 In this case readelf thinks there's alignment padding where there is none, so it starts reading an ELF note in the middle. With newer toolchains (e.g., latest Fedora Rawhide), a similar mismatch triggers a build failure when combined with CONFIG_X86_KERNEL_IBT: btf_encoder__encode: btf__dedup failed! Failed to encode BTF libbpf: failed to find '.BTF' ELF section in vmlinux FAILED: load BTF from vmlinux: No data available make[1]: *** [scripts/Makefile.vmlinux:35: vmlinux] Error 255 This latter error was caused by pahole crashing when it encountered the corrupt .notes section. This crash has been fixed in dwarves version 1.25. As Tianyi Liu describes: "Pahole reads .notes to look for LINUX_ELFNOTE_BUILD_LTO. When LTO is enabled, pahole needs to call cus__merge_and_process_cu to merge compile units, at which point there should only be one unspecified type (used to represent some compilation information) in the global context. However, when the kernel is compiled without LTO, if pahole calls cus__merge_and_process_cu due to alignment issues with notes, multiple unspecified types may appear after merging the cus, and older versions of pahole only support up to one. This is why pahole 1.24 crashes, while newer versions support multiple. However, the latest version of pahole still does not solve the problem of incorrect LTO recognition, so compiling the kernel may be slower than normal." Even with the newer pahole, the note section misaligment issue still exists and pahole is misinterpreting the LTO note. Fix it by discarding the .note.gnu.property section. While GNU properties are important for user space (and VDSO), they don't seem to have any use for vmlinux. (In fact, they're already getting (inadvertently) stripped from vmlinux when CONFIG_DEBUG_INFO_BTF is enabled. The BTF data is extracted from vmlinux.o with "objcopy --only-section=.BTF" into .btf.vmlinux.bin.o. That file doesn't have .note.gnu.property, so when it gets modified and linked back into the main object, the linker automatically strips it (see "How GNU properties are merged" in the ld man page).) Reported-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lkml.kernel.org/bpf/57830c30-cd77-40cf-9cd1-3bb608aa602e@app.fastmail.com Debugged-by: Tianyi Liu <i.pear@outlook.com> Suggested-by: Joan Bruguera Micó <joanbrugueram@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> --- v2: - fixed link - combined discards - updated comment include/asm-generic/vmlinux.lds.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index d1f57e4868ed..cebdf1ca415d 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -891,9 +891,16 @@ /* * Discard .note.GNU-stack, which is emitted as PROGBITS by the compiler. * Otherwise, the type of .notes section would become PROGBITS instead of NOTES. + * + * Also, discard .note.gnu.property, otherwise it forces the notes section to + * be 8-byte aligned which causes alignment mismatches with the kernel's custom + * 4-byte aligned notes. */ #define NOTES \ - /DISCARD/ : { *(.note.GNU-stack) } \ + /DISCARD/ : { \ + *(.note.GNU-stack) \ + *(.note.gnu.property) \ + } \ .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \ BOUNDED_SECTION_BY(.note.*, _notes) \ } NOTES_HEADERS \ -- 2.39.2 ^ permalink raw reply related [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-12 16:30 ` Josh Poimboeuf 2023-04-13 2:21 ` Joan Bruguera Micó @ 2023-04-13 4:54 ` Tianyi Liu 2023-04-16 18:52 ` Joan Bruguera Micó 1 sibling, 1 reply; 29+ messages in thread From: Tianyi Liu @ 2023-04-13 4:54 UTC (permalink / raw) To: jpoimboe Cc: acme, alan.maguire, alexandref75, bpf, dxu, i.pear, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs, joanbrugueram On Wed, Apr 12, 2023 at 16:30PM UTC, Josh Poimboeuf wrote: > On Wed, Apr 12, 2023 at 03:10:14PM +0800, Tianyi Liu wrote: > > On Tue, Apr 11, 2023 at 17:00 , Josh Poimboeuf wrote: > > > On Tue, Feb 14, 2023 at 02:33:02PM +0800, Tianyi Liu wrote: > > > > > LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j > > > > > --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > > > > > .tmp_vmlinux.btf > > > > > btf_encoder__encode: btf__dedup failed! > > > > > Failed to encode BTF > > > > > > > > > > Thanks, > > > > > > > > > > > > > I encountered the same problem when building a new kernel and I found some > > > > reasons for the error. > > > > > > > > In short, enabling CONFIG_X86_KERNEL_IBT will change the order of records in > > > > .notes section. In addition, due to historical problems, the alignment of > > > > records in the .notes section is not unified, which leads to the inability of > > > > gelf_getnote() to read the records after the wrong one. > > > > > > Alexandre, Tianyi, are you still seeing this issue with the latest > > > dwarves? If so can you confirm the below patch fixes it? > > > > > > > Josh, first of all, thank you very much for your help. However, this patch > > doesn't work in my environment. I am using gcc 12.2.1 20230201. > > After compiling, when I use readelf -S to view ELF sections, > > the align of .notes section is still 8: > > > > $ readelf -S .tmp_vmlinux.btf > > [20] .notes NOTE ffffffff8250b570 0170b570 > > 0000000000000084 0000000000000000 A 0 0 8 > > Hm, weird. I have consulted some materials and found that using ALIGN() in linker scripts can only "increase" alignment, not decrease it. Perhaps could you try modifying your patch to use ALIGN(2) and SUBALIGN(2) and see if the .notes section in the output file is aligned to 2? In my tests, this had no effect. [1] https://sourceware.org/binutils/docs/ld/Forced-Output-Alignment.html > > > > Apparently the latest dwarves release fixes it on Fedora Rawhide [1], > > > does anybody know if there a specific dwarves and/or libbpf change for > > > this? > > > > > > > It has been fixed in dwarves[1], but it may just be a coincidence. > > So just to confirm, the btf__dedup error is gone for you with the latest > dwarves? Yes, this issue was fixed after a9498899109d3be14f17abbc322a8f55a1067bee ("dwarf_loader: Fix for BTF id drift caused by adding unspecified types"), which will be included in version 1.25. ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-13 4:54 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Tianyi Liu @ 2023-04-16 18:52 ` Joan Bruguera Micó 2023-04-27 5:14 ` Joan Bruguera Micó 0 siblings, 1 reply; 29+ messages in thread From: Joan Bruguera Micó @ 2023-04-16 18:52 UTC (permalink / raw) To: jpoimboe, i.pear Cc: acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs On Thu, Apr 13, 2023 at 12:54:19PM +0800, Tianyi Liu wrote: > On Wed, Apr 12, 2023 at 16:30PM UTC, Josh Poimboeuf wrote: > > On Wed, Apr 12, 2023 at 03:10:14PM +0800, Tianyi Liu wrote: > > > On Tue, Apr 11, 2023 at 17:00 , Josh Poimboeuf wrote: > > > > On Tue, Feb 14, 2023 at 02:33:02PM +0800, Tianyi Liu wrote: > > > > > > LLVM_OBJCOPY=objcopy pahole -J --btf_gen_floats -j > > > > > > --skip_encoding_btf_inconsistent_proto --btf_gen_optimized > > > > > > .tmp_vmlinux.btf > > > > > > btf_encoder__encode: btf__dedup failed! > > > > > > Failed to encode BTF > > > > > > > > > > > > Thanks, > > > > > > > > > > > > > > > > I encountered the same problem when building a new kernel and I found some > > > > > reasons for the error. > > > > > > > > > > In short, enabling CONFIG_X86_KERNEL_IBT will change the order of records in > > > > > .notes section. In addition, due to historical problems, the alignment of > > > > > records in the .notes section is not unified, which leads to the inability of > > > > > gelf_getnote() to read the records after the wrong one. > > > > > > > > Alexandre, Tianyi, are you still seeing this issue with the latest > > > > dwarves? If so can you confirm the below patch fixes it? > > > > > > > > > > Josh, first of all, thank you very much for your help. However, this patch > > > doesn't work in my environment. I am using gcc 12.2.1 20230201. > > > After compiling, when I use readelf -S to view ELF sections, > > > the align of .notes section is still 8: > > > > > > $ readelf -S .tmp_vmlinux.btf > > > [20] .notes NOTE ffffffff8250b570 0170b570 > > > 0000000000000084 0000000000000000 A 0 0 8 > > > > Hm, weird. > > I have consulted some materials and found that using ALIGN() in linker > scripts can only "increase" alignment, not decrease it. > > Perhaps could you try modifying your patch to use ALIGN(2) and SUBALIGN(2) > and see if the .notes section in the output file is aligned to 2? > In my tests, this had no effect. > > [1] https://sourceware.org/binutils/docs/ld/Forced-Output-Alignment.html Not sure about the ld documentation (it may just be ambiguous wording) but while doing some tests, I have found that Josh's ALIGN/SUBALIGN(4) patch only works for certain kernel configs and fails for others. This likely explains why Josh's patch worked for me but not for Tianyi. I haven't investigated why or when it works though, but here's a config where Josh's ALIGN(4) patch works and or where it doesn't (for me): https://zealcharm.com/20230416-btf-dedup-bug-sample-configs/align-4-working https://zealcharm.com/20230416-btf-dedup-bug-sample-configs/align-4-not-working OTOH the new patch to discard .note.gnu.property works in both cases. ^ permalink raw reply [flat|nested] 29+ messages in thread
* Re: [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes 2023-04-16 18:52 ` Joan Bruguera Micó @ 2023-04-27 5:14 ` Joan Bruguera Micó 0 siblings, 0 replies; 29+ messages in thread From: Joan Bruguera Micó @ 2023-04-27 5:14 UTC (permalink / raw) To: jpoimboe Cc: i.pear, acme, alan.maguire, alexandref75, bpf, dxu, jforbes, linux-kernel, olsajiri, peterz, ptalbert, yhs PS: As additional information for posterity, there are various conditions that explain why this is/was only a problem on some specific distributions: * In addition to dwarves/pahole 1.24, binutils 2.40 seems to also be required for the problem to occur (in Arch, downgrading to binutils 2.39 fixes it). * Debian (and thus derived distributions) configures binutils with `--disable-x86-used-note`, which by default disables emitting the GNU notes which ultimately cause the .notes section to be aligned to 8 bytes. On Debian Bookworm & Ubuntu 23.04, the problem reproduces when building like: ``` export KCFLAGS="-Xassembler -mx86-used-note=yes" export KAFLAGS="-Xassembler -mx86-used-note=yes" make ``` Finally, here's a smaller .config to reproduce the problem on affected systems: https://zealcharm.com/20230416-btf-dedup-bug-sample-configs/minimal-repro ^ permalink raw reply [flat|nested] 29+ messages in thread
end of thread, other threads:[~2023-04-27 5:14 UTC | newest] Thread overview: 29+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-01-22 17:48 Kernel build fail with 'btf_encoder__encode: btf__dedup failed!' Daniel Xu 2023-01-22 21:25 ` Daniel Xu 2023-01-23 8:06 ` Jiri Olsa 2023-01-24 6:13 ` Daniel Xu 2023-01-27 22:28 ` Alexandre Peixoto Ferreira 2023-01-28 0:00 ` Jiri Olsa 2023-01-28 0:21 ` Daniel Xu 2023-01-28 0:23 ` Daniel Xu 2023-01-28 19:23 ` Alexandre Peixoto Ferreira 2023-01-31 15:18 ` Jiri Olsa 2023-02-09 0:21 ` Vicki Pfau 2023-02-09 4:15 ` Alexandre Peixoto Ferreira 2023-02-09 13:07 ` Alan Maguire 2023-02-10 14:02 ` Alexandre Peixoto Ferreira 2023-02-10 14:34 ` Jiri Olsa 2023-02-10 15:37 ` Alexandre Ferreira 2023-02-14 6:33 ` Tianyi Liu 2023-04-11 17:00 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Josh Poimboeuf 2023-04-12 7:10 ` Tianyi Liu 2023-04-12 16:30 ` Josh Poimboeuf 2023-04-13 2:21 ` Joan Bruguera Micó 2023-04-13 9:23 ` Tianyi Liu 2023-04-13 18:59 ` [PATCH] vmlinux.lds.h: Discard .note.gnu.property section Josh Poimboeuf 2023-04-16 19:02 ` Joan Bruguera Micó 2023-04-18 21:47 ` Josh Poimboeuf 2023-04-18 21:49 ` [PATCH v2] " Josh Poimboeuf 2023-04-13 4:54 ` [PATCH] vmlinux.lds.h: Force-align ELF notes section to four bytes Tianyi Liu 2023-04-16 18:52 ` Joan Bruguera Micó 2023-04-27 5:14 ` Joan Bruguera Micó
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