libperf: Add NULL pointer check for cpu_map iteration and NULL assignment for all_cpus.

A NULL pointer may be passed to perf_cpu_map__cpu and then cause a
crash, such as the one commit cb71f7d43ece ("libperf: Setup initial
evlist::all_cpus value") fix.

Signed-off-by: He Zhe <zhe.he@windriver.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kyle Meyer <meyerk@hpe.com>
Link: http://lore.kernel.org/lkml/1583665157-349023-1-git-send-email-zhe.he@windriver.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
index f93f4e7..ca02150 100644 (file)
--- a/tools/lib/perf/cpumap.c
+++ b/tools/lib/perf/cpumap.c
@@ -247,7 +247,7 @@ out:
 
 int perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx)
 {
-       if (idx < cpus->nr)
+       if (cpus && idx < cpus->nr)
                return cpus->map[idx];
 
        return -1;

diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index def5505..c481b62 100644 (file)
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -125,6 +125,7 @@ void perf_evlist__exit(struct perf_evlist *evlist)
        perf_cpu_map__put(evlist->cpus);
        perf_thread_map__put(evlist->threads);
        evlist->cpus = NULL;
+       evlist->all_cpus = NULL;
        evlist->threads = NULL;
        fdarray__exit(&evlist->pollfd);
 }