Re: [PATCH] perf bpf: Return NULL when RB tree lookup fails in perf_env__find_btf()

[Song Liu <songliubraving@fb.com>]

> On Apr 17, 2019, at 7:55 AM, Jiri Olsa <jolsa@kernel.org> wrote:
> 
> We currently don't return NULL in case we don't find the
> bpf_prog_info_node, fixing that.
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Song Liu <songliubraving@fb.com>
> Fixes: 3792cb2ff43b ("perf bpf: Save BTF in a rbtree in perf_env")
> Link: http://lkml.kernel.org/n/tip-99g9rg4p20a1o99vr0nkjhq8@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Acked-by: Song Liu <songliubraving@fb.com>

Thanks again for the fix!

> ---
> tools/perf/util/env.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index 34a363f2e71b..9494f9dc61ec 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -111,10 +111,12 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> 		else if (btf_id > node->id)
> 			n = n->rb_right;
> 		else
> -			break;
> +			goto out;
> 	}
> +	node = NULL;
> 
> 	up_read(&env->bpf_progs.lock);
> +out:
> 	return node;
> }
> 
> -- 
> 2.17.2
>