On Fri, Jan 10, 2025 at 10:39:50AM +0000, Alan Maguire wrote: > On 10/01/2025 02:31, Ihor Solodrai wrote: > > BPF CI caught a segfault on aarch64 and s390x [1] after recent merges > > into the master branch. > > > > The segfault happened at free(func_state->annots) in > > btf_encoder__delete_saved_funcs(). > > > > func_state->annots arrived there uninitialized because after patch [2] > > in some cases func_state may be allocated with a realloc, but was not > > zeroed out. > > > > Fix this bug by always memset-ing a func_state to zero in > > btf_encoder__alloc_func_state(). > > > > [1] https://github.com/kernel-patches/bpf/actions/runs/12700574327 > > [2] https://lore.kernel.org/dwarves/20250109185950.653110-11-ihor.solodrai@xxxxx/ > > > Thanks for the quick fix! Reproduced this on an aarch64 system: > > BTF [M] kernel/resource_kunit.ko > /bin/sh: line 1: 630875 Segmentation fault (core dumped) > LLVM_OBJCOPY="objcopy" pahole -J -j > --btf_features=encode_force,var,float,enum64,decl_tag,type_tag,optimized_func,consistent_func,decl_tag_kfuncs > --lang_exclude=rust --btf_base ./vmlinux kernel/kcsan/kcsan_test.ko > make[2]: *** [scripts/Makefile.modfinal:57: kernel/kcsan/kcsan_test.ko] > Error 139 > make[2]: *** Deleting file 'kernel/kcsan/kcsan_test.ko' > make[2]: *** Waiting for unfinished jobs.... > /bin/sh: line 1: 630907 Segmentation fault (core dumped) > LLVM_OBJCOPY="objcopy" pahole -J -j > --btf_features=encode_force,var,float,enum64,decl_tag,type_tag,optimized_func,consistent_func,decl_tag_kfuncs > --lang_exclude=rust --btf_base ./vmlinux kernel/torture.ko > make[2]: *** [scripts/Makefile.modfinal:56: kernel/torture.ko] Error 139 > make[2]: *** Deleting file 'kernel/torture.ko' > > ...and verified that with the fix all works well. > > Nit: missing Signed-off-by I'm adding it, ok? - Arnaldo > Tested-by: Alan Maguire <alan.maguire@xxxxxxxxxx> Thanks! > > --- > > btf_encoder.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/btf_encoder.c b/btf_encoder.c > > index 78efd70..511c1ea 100644 > > --- a/btf_encoder.c > > +++ b/btf_encoder.c > > @@ -1083,7 +1083,7 @@ static bool funcs__match(struct btf_encoder_func_state *s1, > > > > static struct btf_encoder_func_state *btf_encoder__alloc_func_state(struct btf_encoder *encoder) > > { > > - struct btf_encoder_func_state *tmp; > > + struct btf_encoder_func_state *state, *tmp; > > > > if (encoder->func_states.cnt >= encoder->func_states.cap) { > > > > @@ -1100,7 +1100,10 @@ static struct btf_encoder_func_state *btf_encoder__alloc_func_state(struct btf_e > > encoder->func_states.array = tmp; > > } > > > > - return &encoder->func_states.array[encoder->func_states.cnt++]; > > + state = &encoder->func_states.array[encoder->func_states.cnt++]; > > + memset(state, 0, sizeof(*state)); > > + > > + return state; > > } > > > > static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct function *fn, struct elf_function *func)
