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

[Jiri Olsa <olsajiri@gmail.com>]

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