On Mon, Oct 26, 2020 at 1:32 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> On Mon, Oct 26, 2020 at 04:58:30PM -0300, Arnaldo Carvalho de Melo wrote:
> > Hi guys,
> >
> > I just stumbled on this, investigating... This is with what is
> > in the tmp branch at
> > git://git.kernel.org/pub/scm/devel/pahole/pahole.git.
> >
> > error: found variable in CU '/home/acme/git/linux/security/selinux/hooks.c' that has void type
> > Encountered error while encoding BTF.
> > LD .tmp_vmlinux.kallsyms1
> > KSYMS .tmp_vmlinux.kallsyms1.S
> > AS .tmp_vmlinux.kallsyms1.S
> > LD .tmp_vmlinux.kallsyms2
> > KSYMS .tmp_vmlinux.kallsyms2.S
> > AS .tmp_vmlinux.kallsyms2.S
> > LD vmlinux
> > BTFIDS vmlinux
> > FAILED: load BTF from vmlinux: Unknown error -2make[1]: *** [/home/acme/git/linux/Makefile:1164: vmlinux] Error 255
> > make[1]: Leaving directory '/home/acme/git/build/v5.10.0-rc1+'
> > make: *** [Makefile:185: __sub-make] Error 2
>
> yep, I see the same and when I use --btf_encode_force,
> it shows more of them:
>
> error: found variable in CU 'arch/x86/kernel/cpu/mce/core.c' that has void type
> error: found variable in CU 'security/selinux/hooks.c' that has void type
> error: found variable in CU 'security/selinux/hooks.c' that has void type
> error: found variable in CU 'security/selinux/hooks.c' that has void type
> error: found variable in CU 'security/selinux/hooks.c' that has void type
> error: found variable in CU 'security/selinux/hooks.c' that has void type
> error: found variable in CU 'security/selinux/hooks.c' that has void type
> error: found variable in CU 'drivers/platform/x86/intel_pmc_core.c' that has void type
>
> I have no idea how variables are encoded in dwarf,
> but I wonder it's another gcc bug ;-)
>
> jirka
>
Still looking. But I found if I move
c815d266 (Hao Luo 2020-08-24 17:45:23 -0700 444)
if (var->ip.tag.type == 0) {
2e719cca (Andrii Nakryiko 2020-10-08 16:39:57 -0700 445)
fprintf(stderr, "error: found variable in CU '%s'
that has void type\n",
2e719cca (Andrii Nakryiko 2020-10-08 16:39:57 -0700 446)
cu->name);
f3d9054b (Hao Luo 2020-07-08 13:44:10 -0700 447)
if (force)
f3d9054b (Hao Luo 2020-07-08 13:44:10 -0700 448)
continue;
f3d9054b (Hao Luo 2020-07-08 13:44:10 -0700 449)
err = -1;
f3d9054b (Hao Luo 2020-07-08 13:44:10 -0700 450)
break;
f3d9054b (Hao Luo 2020-07-08 13:44:10 -0700 451)
}
f3d9054b (Hao Luo 2020-07-08 13:44:10 -0700 452)
after
2e719cca (Andrii Nakryiko 2020-10-08 16:39:57 -0700 453)
type = var->ip.tag.type + type_id_off;
2e719cca (Andrii Nakryiko 2020-10-08 16:39:57 -0700 454)
linkage = var->external ? BTF_VAR_GLOBAL_ALLOCATED :
BTF_VAR_STATIC;
2e719cca (Andrii Nakryiko 2020-10-08 16:39:57 -0700 455)
if (!percpu_var_exists(addr, &size, &name))
2e719cca (Andrii Nakryiko 2020-10-08 16:39:57 -0700 456)
continue; /* not a per-CPU variable */
the error is gone. I think we should check percpu_var_exists() before
checking var->ip.tag.type.
Hao
