On Fri, Aug 9, 2024 at 4:32 AM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> Hello Andrii Nakryiko,
>
> This is a semi-automatic email about new static checker warnings.
>
> Commit c381203eadb7 ("selftests/bpf: add trusted global subprog arg
> tests") from Jan 29, 2024, leads to the following Smatch complaint:
>
> ./tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c:88 trusted_task_arg_nonnull_fail2()
> warn: variable dereferenced before check 'nullable' (see line 86)
>
> ./tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c
> 85 /* should fail, PTR_TO_BTF_ID_OR_NULL */
> 86 res = subprog_trusted_task_nonnull(nullable);
> ^^^^^^^^
> This is dereferenced
this is intentional, it's testing that verifier will catch this mistake
>
> 87
> 88 if (nullable)
> ^^^^^^^^
> NULL check is too late
>
> 89 bpf_task_release(nullable);
> 90
>
> regards,
> dan carpenter
