[PATCH v2 3/4] perf-probe: Fix memory leakage when the probe point is not found

From: Masami Hiramatsu <mhiramat@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, mhiramat@kernel.org,
	Andi Kleen <andi@firstfloor.org>, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH v2 3/4] perf-probe: Fix memory leakage when the probe point is not found
Date: Fri, 10 Jul 2020 22:11:23 +0900	[thread overview]
Message-ID: <159438668346.62703.10887420400718492503.stgit@devnote2> (raw)
In-Reply-To: <159438665389.62703.13848613271334658629.stgit@devnote2>

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.

Fixes: ff741783506c ("perf probe: Introduce debuginfo to encapsulate dwarf information")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 tools/perf/util/probe-finder.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 9963e4e8ea20..659024342e9a 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -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);

