On Thu, Feb 9, 2023 at 5:29 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote: > > v1.25 of pahole supports filtering out functions with multiple > inconsistent function prototypes or optimized-out parameters > from the BTF representation. These present problems because > there is no additional info in BTF saying which inconsistent > prototype matches which function instance to help guide > attachment, and functions with optimized-out parameters can > lead to incorrect assumptions about register contents. > > So for now, filter out such functions while adding BTF > representations for functions that have "."-suffixes > (foo.isra.0) but not optimized-out parameters. > > This patch assumes changes in [1] land and pahole is bumped > to v1.25. > > [1] https://lore.kernel.org/bpf/1675790102-23037-1-git-send-email-alan.maguire@xxxxxxxxxx/ > > Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx> > Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> > > --- > scripts/pahole-flags.sh | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh > index 1f1f1d3..728d551 100755 > --- a/scripts/pahole-flags.sh > +++ b/scripts/pahole-flags.sh > @@ -23,5 +23,8 @@ if [ "${pahole_ver}" -ge "124" ]; then > # see PAHOLE_HAS_LANG_EXCLUDE > extra_paholeopt="${extra_paholeopt} --lang_exclude=rust" > fi > +if [ "${pahole_ver}" -ge "125" ]; then > + extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_inconsistent_proto --btf_gen_optimized" > +fi We landed this too soon. #229 tracing_struct:FAIL is failing now. since bpf_testmod.ko is missing a bunch of functions though they're global. I've tried a bunch of different flags and attributes, but none of them helped. The only thing that works is: diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 46500636d8cd..5fd0f75d5d20 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -28,6 +28,7 @@ struct bpf_testmod_struct_arg_2 { long b; }; +__attribute__((optimize("-O0"))) noinline int bpf_testmod_test_struct_arg_1(struct bpf_testmod_struct_arg_2 a, int b, int c) { We cannot do: --- a/tools/testing/selftests/bpf/bpf_testmod/Makefile +++ b/tools/testing/selftests/bpf/bpf_testmod/Makefile @@ -10,7 +10,7 @@ endif MODULES = bpf_testmod.ko obj-m += bpf_testmod.o -CFLAGS_bpf_testmod.o = -I$(src) +CFLAGS_bpf_testmod.o = -I$(src) -O0 The build fails due to asm stuff. Maybe we should make scripts/pahole-flags.sh selective and don't apply skip_encoding_btf_inconsiste to bpf_testmod ? Thoughts?
