Re: [PATCH bpf-next v2 5/9] selftests: bpf: Update failure message for rbtree_fail

["Emil Tsalapatis" <emil@etsalapatis.com>]

On Wed Dec 31, 2025 at 12:08 PM EST, Puranjay Mohan wrote:
> The rbtree_api_use_unchecked_remove_retval() selftest passes a pointer
> received from bpf_rbtree_remove() to bpf_rbtree_add() without checking
> for NULL, this was earlier caught by __check_ptr_off_reg() in the
> verifier. Now the verifier assumes every kfunc only takes trusted pointer
> arguments, so it catches this NULL pointer earlier in the path and
> provides a more accurate failure message.
>
> Signed-off-by: Puranjay Mohan <puranjay@kernel.org>

Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>

> ---
>  tools/testing/selftests/bpf/progs/rbtree_fail.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/rbtree_fail.c b/tools/testing/selftests/bpf/progs/rbtree_fail.c
> index 4acb6af2dfe3..70b7baf9304b 100644
> --- a/tools/testing/selftests/bpf/progs/rbtree_fail.c
> +++ b/tools/testing/selftests/bpf/progs/rbtree_fail.c
> @@ -153,7 +153,7 @@ long rbtree_api_add_to_multiple_trees(void *ctx)
>  }
>  
>  SEC("?tc")
> -__failure __msg("dereference of modified ptr_or_null_ ptr R2 off=16 disallowed")
> +__failure __msg("Possibly NULL pointer passed to trusted arg1")
>  long rbtree_api_use_unchecked_remove_retval(void *ctx)
>  {
>  	struct bpf_rb_node *res;