[PATCH AUTOSEL 4.14 112/127] perf parse-events: Fix incorrect conversion of 'if () free()' to 'zfree()'

From: Sasha Levin
Date: Thu Sep 17 2020 - 22:30:45 EST

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

[ Upstream commit 7fcdccd4237724931d9773d1e3039bfe053a6f52 ]

When applying a patch by Ian I incorrectly converted to zfree() an
expression that involved testing some other struct member, not the one
being freed, which lead to bugs reproduceable by:

$ perf stat -e i/bs,tsc,L2/o sleep 1
WARNING: multiple event parsing errors
Segmentation fault (core dumped)

Fix it by restoring the test for pos->free_str before freeing
pos->val.str, but continue using zfree(&pos->val.str) to set that member
to NULL after freeing it.

Reported-by: Ian Rogers <irogers@xxxxxxxxxx>
Fixes: e8dfb81838b1 ("perf parse-events: Fix memory leaks found on parse_events")
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: clang-built-linux@xxxxxxxxxxxxxxxx
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
tools/perf/util/parse-events.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 2733cdfdf04c6..ba973bdfaa657 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1258,7 +1258,8 @@ static int __parse_events_add_pmu(struct parse_events_state *parse_state,

list_for_each_entry_safe(pos, tmp, &config_terms, list) {
- zfree(&pos->val.str);
+ if (pos->free_str)
+ zfree(&pos->val.str);
return -EINVAL;