Re: Kernel build fail with 'btf_encoder__encode: btf__dedup failed!'

[Jiri Olsa <olsajiri@gmail.com>]

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