[ Upstream commit cf30ae726c011e0372fd4c2d588466c8b50a8907 ]
The buffer containing the string used to set cpumask is overwritten at the end of the 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 the cpumask string size.
Signed-off-by: He Zhe zhe.he@windriver.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Alexey Budankov alexey.budankov@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Stephane Eranian eranian@google.com Fixes: dc23103278c5 ("perf ftrace: Add support for -a and -C option") Link: http://lkml.kernel.org/r/1564734592-15624-1-git-send-email-zhe.he@windriver.... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 25a42acabee18..13a33fb71a6da 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -162,7 +162,7 @@ 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);