Re: [PATCH] selftests/bpf: Fix the address is NULL

[Yonghong Song]

On 6/14/23 12:42 AM, wuyonggang001@xxxxxxxxxx wrote:
> Fix the following coccicheck error:
>
> tools/testing/selftests/bpf/progs/test_ksyms_weak.c:53:6-20: ERROR: test 
> of a variable/field address

I didn't see clang/gcc compiler warns about this. Maybe need some
additional flags beyond what current selftest/bpf already has
in order to trigger this warning?
If you feel this warning has some merit, could you propose
it to gcc/llvm community?

> Signed-off-by: Yonggang Wu <wuyonggang001@xxxxxxxxxx>
> ---
>   tools/testing/selftests/bpf/progs/test_ksyms_weak.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c 
> b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
> index d00268c91e19..768a4d6ee6f5 100644
> --- a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
> +++ b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
> @@ -50,7 +50,7 @@ int pass_handler(const void *ctx)
>       /* tests non-existent symbols. */
>       out__non_existent_typed = (__u64)&bpf_link_fops2;
>
> -    if (&bpf_link_fops2) /* can't happen */
> +    if (&bpf_link_fops2 != NULL) /* can't happen */
>           out__non_existent_typed = 
> (__u64)bpf_per_cpu_ptr(&bpf_link_fops2, 0);
>
>       if (!bpf_ksym_exists(bpf_task_acquire))