[tip:perf/urgent] perf tools: Fix find_perf_probe_point_from_map( ) which incorrectly returns success

[tip-bot for Wang Nan]

Commit-ID:  98d3b258ede2cdac31a2728543f652964e597e79
Gitweb:     http://git.kernel.org/tip/98d3b258ede2cdac31a2728543f652964e597e79
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Thu, 5 Nov 2015 13:19:25 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 5 Nov 2015 12:47:52 -0300

perf tools: Fix find_perf_probe_point_from_map() which incorrectly returns success

It is possible that find_perf_probe_point_from_map() fails to find a
symbol but still returns 0 because of an small error when coding:
find_perf_probe_point_from_map() set 'ret' to error code at first, but
also use it to hold return value of kernel_get_symbol_address_by_name().

This patch resets 'ret' to error even kernel_get_symbol_address_by_name()
success, so if !sym, the whole function returns error correctly.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1446729565-27592-3-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/probe-event.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index b51a8bf..e659c4f 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1905,6 +1905,9 @@ static int find_perf_probe_point_from_map(struct probe_trace_point *tp,
 			sym = __find_kernel_function(addr, &map);
 		}
 	}
+
+	/* ret may has be overwritten so reset it */
+	ret = -ENOENT;
 	if (!sym)
 		goto out;
 
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