FAILED: patch "[PATCH] perf probe: Fix memory leakage when the probe point is not" failed to apply to 5.4-stable tree

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 12d572e785b15bc764e956caaa8a4c846fd15694 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <[email protected]>
Date: Fri, 10 Jul 2020 22:11:23 +0900
Subject: [PATCH] perf probe: Fix memory leakage when the probe point is not
found

Fix the memory leakage in debuginfo__find_trace_events() when the probe point is not found in the debuginfo. If there is no probe point found in the debuginfo, debuginfo__find_probes() will NOT return -ENOENT, but 0.

Thus the caller of debuginfo__find_probes() must check the tf.ntevs and release the allocated memory for the array of struct probe_trace_event.

The current code releases the memory only if the debuginfo__find_probes() hits an error but not checks tf.ntevs. In the result, the memory allocated on *tevs are not released if tf.ntevs == 0.

This fixes the memory leakage by checking tf.ntevs == 0 in addition to ret < 0.

index 9963e4e8ea20..659024342e9a 100644
@@ -1467,7 +1467,7 @@ int debuginfo__find_trace_events(struct debuginfo *dbg,
 	if (ret >= 0 && tf.pf.skip_empty_arg)
 		ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
 
-	if (ret < 0) {
+	if (ret < 0 || tf.ntevs == 0) {
 		for (i = 0; i < tf.ntevs; i++)
 			clear_probe_trace_event(&tf.tevs[i]);
 		zfree(tevs);