linux-kernel - [PATCH v2] perf report: fix memory leak in addr2line when called by addr2inlines

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Message-Id: <20170518083753.14337-1-milian.wolff@kdab.com>
Date:   Thu, 18 May 2017 10:37:53 +0200
From:   Milian Wolff <milian.wolff@...b.com>
To:     Linux-kernel@...r.kernel.org
Cc:     linux-perf-users@...r.kernel.org,
        Milian Wolff <milian.wolff@...b.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        David Ahern <dsahern@...il.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Yao Jin <yao.jin@...ux.intel.com>
Subject: [PATCH v2] perf report: fix memory leak in addr2line when called by addr2inlines

When a filename was found in addr2line it was duplicated via strdup
but never freed. Now we pass NULL and handle this gracefully in
addr2line.

Detected by Valgrind:

==16331== 1,680 bytes in 21 blocks are definitely lost in loss record 148 of 220
==16331==    at 0x4C2AF1F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==16331==    by 0x672FA69: strdup (in /usr/lib/libc-2.25.so)
==16331==    by 0x52769F: addr2line (srcline.c:256)
==16331==    by 0x52769F: addr2inlines (srcline.c:294)
==16331==    by 0x52769F: dso__parse_addr_inlines (srcline.c:502)
==16331==    by 0x574D7A: inline__fprintf (hist.c:41)
==16331==    by 0x574D7A: ipchain__fprintf_graph (hist.c:147)
==16331==    by 0x57518A: __callchain__fprintf_graph (hist.c:212)
==16331==    by 0x5753CF: callchain__fprintf_graph.constprop.6 (hist.c:337)
==16331==    by 0x57738E: hist_entry__fprintf (hist.c:628)
==16331==    by 0x57738E: hists__fprintf (hist.c:882)
==16331==    by 0x44A20F: perf_evlist__tty_browse_hists (builtin-report.c:399)
==16331==    by 0x44A20F: report__browse_hists (builtin-report.c:491)
==16331==    by 0x44A20F: __cmd_report (builtin-report.c:624)
==16331==    by 0x44A20F: cmd_report (builtin-report.c:1054)
==16331==    by 0x4A49CE: run_builtin (perf.c:296)
==16331==    by 0x4A4CC0: handle_internal_command (perf.c:348)
==16331==    by 0x434371: run_argv (perf.c:392)
==16331==    by 0x434371: main (perf.c:530)

Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Yao Jin <yao.jin@...ux.intel.com>
Signed-off-by: Milian Wolff <milian.wolff@...b.com>
---
 tools/perf/util/srcline.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

v2:
- keep behavior of old function when strdup failed
- set ret to 1 if we found any inline node

diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index df051a52393c..5e376d64d59e 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -230,7 +230,10 @@ static int addr2line(const char *dso_name, u64 addr,
 
 	bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l);
 
-	if (a2l->found && unwind_inlines) {
+	if (!a2l->found)
+		return 0;
+
+	if (unwind_inlines) {
 		int cnt = 0;
 
 		while (bfd_find_inliner_info(a2l->abfd, &a2l->filename,
@@ -243,6 +246,8 @@ static int addr2line(const char *dso_name, u64 addr,
 							a2l->line, node,
 							dso) != 0)
 					return 0;
+				// found at least one inline frame
+				ret = 1;
 			}
 		}
 
@@ -252,14 +257,14 @@ static int addr2line(const char *dso_name, u64 addr,
 		}
 	}
 
-	if (a2l->found && a2l->filename) {
-		*file = strdup(a2l->filename);
-		*line = a2l->line;
-
-		if (*file)
-			ret = 1;
+	if (file) {
+		*file = a2l->filename ? strdup(a2l->filename) : NULL;
+		ret = *file ? 1 : 0;
 	}
 
+	if (line)
+		*line = a2l->line;
+
 	return ret;
 }
 
@@ -278,8 +283,6 @@ void dso__free_a2l(struct dso *dso)
 static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
 	struct dso *dso)
 {
-	char *file = NULL;
-	unsigned int line = 0;
 	struct inline_node *node;
 
 	node = zalloc(sizeof(*node));
@@ -291,7 +294,7 @@ static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
 	INIT_LIST_HEAD(&node->val);
 	node->addr = addr;
 
-	if (!addr2line(dso_name, addr, &file, &line, dso, TRUE, node))
+	if (!addr2line(dso_name, addr, NULL, NULL, dso, TRUE, node))
 		goto out_free_inline_node;
 
 	if (list_empty(&node->val))
-- 
2.13.0