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Subject[PATCH 02/31] perf parse-events: Add defensive NULL check
Date
From: Ian Rogers <irogers@google.com>

Terms may have a NULL config in which case a strcmp will SEGV. This can
be reproduced with:

perf stat -e '*/event=?,nr/' sleep 1

Add a NULL check to avoid this. This was caught by LLVM's libfuzzer.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: clang-built-linux@googlegroups.com
Link: http://lore.kernel.org/lkml/20200325164022.41385-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/pmu.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 616fbda7c3fc..ef6a63f3d386 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -984,12 +984,11 @@ static int pmu_resolve_param_term(struct parse_events_term *term,
struct parse_events_term *t;

list_for_each_entry(t, head_terms, list) {
- if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
- if (!strcmp(t->config, term->config)) {
- t->used = true;
- *value = t->val.num;
- return 0;
- }
+ if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM &&
+ t->config && !strcmp(t->config, term->config)) {
+ t->used = true;
+ *value = t->val.num;
+ return 0;
}
}

--
2.21.1
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