perf evlist: Fix alloc_mmap() failure path

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

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Fixes: d4c6fb36ac2c ("perf evsel: Record fd into perf_mmap")
Link: http://lkml.kernel.org/r/1464699975-230440-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index e0f3094..1b918aa 100644 (file)
--- 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 {