Re: [PATCH bpf] libbpf: don't close(-1) in multi-uprobe feature detector

[Jiri Olsa <olsajiri@gmail.com>]

On Wed, May 29, 2024 at 04:12:12PM -0700, Andrii Nakryiko wrote:
> Guard close(link_fd) with extra link_fd >= 0 check to prevent close(-1).
> 
> Detected by Coverity static analysis.
> 
> Fixes: 04d939a2ab22 ("libbpf: detect broken PID filtering logic for multi-uprobe")
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
>  tools/lib/bpf/features.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c
> index 3df0125ed5fa..50befe125ddc 100644
> --- a/tools/lib/bpf/features.c
> +++ b/tools/lib/bpf/features.c
> @@ -393,7 +393,8 @@ static int probe_uprobe_multi_link(int token_fd)
>  	err = -errno; /* close() can clobber errno */
>  
>  	if (link_fd >= 0 || err != -EBADF) {
> -		close(link_fd);
> +		if (link_fd >= 0)
> +			close(link_fd);
>  		close(prog_fd);
>  		return 0;
>  	}
> -- 
> 2.43.0
> 
>