On Wed, Nov 23, 2022 at 7:58 AM Yonghong Song <yhs@xxxxxx> wrote: > > With CONFIG_DEBUG_INFO_BTF not set, we hit the following compilation error, > /.../kernel/bpf/verifier.c:8196:23: error: array index 6 is past the end of the array > (that has type 'u32[5]' (aka 'unsigned int[5]')) [-Werror,-Warray-bounds] > if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) > ^ ~~~~~~~~~~~~~~~~~~~~~~~ > /.../kernel/bpf/verifier.c:8174:1: note: array 'special_kfunc_list' declared here > BTF_ID_LIST(special_kfunc_list) > ^ > /.../include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST' > #define BTF_ID_LIST(name) static u32 __maybe_unused name[5]; > ^ > /.../kernel/bpf/verifier.c:8443:19: error: array index 5 is past the end of the array > (that has type 'u32[5]' (aka 'unsigned int[5]')) [-Werror,-Warray-bounds] > btf_id == special_kfunc_list[KF_bpf_list_pop_back]; > ^ ~~~~~~~~~~~~~~~~~~~~ > /.../kernel/bpf/verifier.c:8174:1: note: array 'special_kfunc_list' declared here > BTF_ID_LIST(special_kfunc_list) > ^ > /.../include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST' > #define BTF_ID_LIST(name) static u32 __maybe_unused name[5]; > ... > > Fix the problem by increase the size of BTF_ID_LIST to 8 to avoid compilation error > and also prevent potentially unintended issue due to out-of-bound access. > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Reported-by: Dan Carpenter <error27@xxxxxxxxx> > Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx> > Signed-off-by: Yonghong Song <yhs@xxxxxx> > --- > include/linux/btf_ids.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h > index c9744efd202f..71d0ce707744 100644 > --- a/include/linux/btf_ids.h > +++ b/include/linux/btf_ids.h > @@ -204,7 +204,7 @@ extern struct btf_id_set8 name; > > #else > > -#define BTF_ID_LIST(name) static u32 __maybe_unused name[5]; > +#define BTF_ID_LIST(name) static u32 __maybe_unused name[8]; Changed it to 16 while applying so we don't have to bump it again in the near future when another special kfunc is added.
