From: He Zhe <[email protected]> The buffer containing string used to set cpumask is overwritten by end of string later in cpu_map__snprint_mask due to not enough memory space, when there is only one cpu. And thus causes the following failure.
$ perf ftrace ls failed to reset ftrace This patch fixes the calculation of cpumask string size. Signed-off-by: He Zhe <[email protected]> --- tools/perf/builtin-ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 66d5a66..0193128 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -173,7 +173,7 @@ static int set_tracing_cpumask(struct cpu_map *cpumap) int last_cpu; last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1); - mask_size = (last_cpu + 3) / 4 + 1; + mask_size = last_cpu / 4 + 2; /* one more byte for EOS */ mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */ cpumask = malloc(mask_size); -- 2.7.4
