bpf: Fix uninitialized symbol in bpf_perf_link_fill_kprobe()

The patch 1b715e1: "bpf: Support ->fill_link_info for perf_event" from Jul 9, 2023, leads to the following Smatch static checker warning: kernel/bpf/syscall.c:3416 bpf_perf_link_fill_kprobe() error: uninitialized symbol 'type'. That can happens when uname is NULL. So fix it by verifying the uname when we really need to fill it. Fixes: 1b715e1 ("bpf: Support ->fill_link_info for perf_event") Reported-by: Dan Carpenter <[email protected]> Closes: https://lore.kernel.org/bpf/[email protected]/ Signed-off-by: Yafang Shao <[email protected]> Acked-by: Yonghong Song <[email protected]>
kernel-patches · Aug 4, 2023 · 45022c4 · 45022c4
1 parent 83f304b
commit 45022c4
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
@@ -3378,14 +3378,14 @@ static int bpf_perf_link_fill_common(const struct perf_event *event,
 
 	if (!ulen ^ !uname)
 		return -EINVAL;
-	if (!uname)
-		return 0;
 
 	err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf,
 				      probe_offset, probe_addr);
 	if (err)
 		return err;
 
+	if (!uname)
+		return 0;
 	if (buf) {
 		len = strlen(buf);
 		err = bpf_copy_to_user(uname, buf, ulen, len);