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

[Andrii Nakryiko <andrii@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 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