From: He Zhe <[email protected]> cpu_map__snprint_mask() would write to illegal memory pointed by zalloc(0) when there is only one cpu.
This patch fixes the calculation and adds sanity check against the input parameters. Signed-off-by: He Zhe <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Alexey Budankov <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kan Liang <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Fixes: 4400ac8a9a90 ("perf cpumap: Introduce cpu_map__snprint_mask()") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/cpumap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c index 3acfbe34ebaf..39cce66b4ebc 100644 --- a/tools/perf/util/cpumap.c +++ b/tools/perf/util/cpumap.c @@ -751,7 +751,10 @@ size_t cpu_map__snprint_mask(struct cpu_map *map, char *buf, size_t size) unsigned char *bitmap; int last_cpu = cpu_map__cpu(map, map->nr - 1); - bitmap = zalloc((last_cpu + 7) / 8); + if (buf == NULL) + return 0; + + bitmap = zalloc(last_cpu / 8 + 1); if (bitmap == NULL) { buf[0] = '\0'; return 0; -- 2.21.0
