From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Thu, 18 Jul 2019 14:28:37 +0000 (-0300)
Subject: perf probe: Avoid calling freeing routine multiple times for same pointer
X-Git-Tag: v4.14.139~29
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=79ba04ff40fd476f2d66eadb045a7c1f31d5d215;p=users%2Fdwmw2%2Flinux.git

perf probe: Avoid calling freeing routine multiple times for same pointer

[ Upstream commit d95daf5accf4a72005daa13fbb1d1bd8709f2861 ]

When perf_add_probe_events() we call cleanup_perf_probe_events() for the
pev pointer it receives, then, as part of handling this failure the main
'perf probe' goes on and calls cleanup_params() and that will again call
cleanup_perf_probe_events()for the same pointer, so just set nevents to
zero when handling the failure of perf_add_probe_events() to avoid the
double free.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-x8qgma4g813z96dvtw9w219q@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index c0065923a525f..e1ac51aaedcff 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -712,6 +712,16 @@ __cmd_probe(int argc, const char **argv)
 
 		ret = perf_add_probe_events(params.events, params.nevents);
 		if (ret < 0) {
+
+			/*
+			 * When perf_add_probe_events() fails it calls
+			 * cleanup_perf_probe_events(pevs, npevs), i.e.
+			 * cleanup_perf_probe_events(params.events, params.nevents), which
+			 * will call clear_perf_probe_event(), so set nevents to zero
+			 * to avoid cleanup_params() to call clear_perf_probe_event() again
+			 * on the same pevs.
+			 */
+			params.nevents = 0;
 			pr_err_with_code("  Error: Failed to add events.", ret);
 			return ret;
 		}