[PATCH] perf tools: Fix perf_evlist__alloc_mmap() failure path

[Wang Nan]

If zalloc fail, setting evlist->mmap[i].fd is unsafe.
perf_evlist__alloc_mmap() should fail right after zalloc() fail.

Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Masami Hiramatsu <mhira...@kernel.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
 tools/perf/util/evlist.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index e0f3094..1b918aa 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -946,9 +946,12 @@ static int perf_evlist__alloc_mmap(struct perf_evlist 
*evlist)
        if (cpu_map__empty(evlist->cpus))
                evlist->nr_mmaps = thread_map__nr(evlist->threads);
        evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
+       if (!evlist->mmap)
+               return -ENOMEM;
+
        for (i = 0; i < evlist->nr_mmaps; i++)
                evlist->mmap[i].fd = -1;
-       return evlist->mmap != NULL ? 0 : -ENOMEM;
+       return 0;
 }
 
 struct mmap_params {
-- 
1.8.3.4