On Mon, Oct 26, 2020 at 03:18:22PM -0700, Hao Luo wrote:
> Commit 2e719cc ("btf_encoder: revamp how per-CPU variables are
> encoded") adds percpu_var_exists() to filter out the symbols that
> are not percpu var. However, the check comes after checking the
> var's type. There can be symbols that are of zero type. If we hit
> that, btf_encoder will not work without '--btf_encode_force'.
> So we should check percpu_var_exists before checking var's type.
>
> Tested:
> haoluo@haoluo:~/kernel/tip$ gcc --version
> gcc (GCC) 10.2.0
> Copyright (C) 2020 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> Before:
>
> haoluo@haoluo:~/kernel/tip$ make clean -s
> haoluo@haoluo:~/kernel/tip$ make -j 32 -s
> LINK resolve_btfids
> error: found variable in CU 'kernel/bpf/btf.c' that has void type
> Encountered error while encoding BTF.
> FAILED: load BTF from vmlinux: Unknown error -2make: *** [Makefile:1164: vmlinux] Error 255
>
> After:
>
> haoluo@haoluo:~/kernel/tip$ make clean -s
> haoluo@haoluo:~/kernel/tip$ make -j 32 -s
> LINK resolve_btfids
> haoluo@haoluo:~/kernel/tip$
>
> Fixes: 2e719cc ("btf_encoder: revamp how per-CPU variables are encoded")
> Signed-off-by: Hao Luo <haoluo@xxxxxxxxxx>
it fixes the build issue for me
Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
thanks,
jirka
