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)

Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yao Jin <yao.jin@linux.intel.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170524062129.32529-3-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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))