Commit-ID: cf30ae726c011e0372fd4c2d588466c8b50a8907 Gitweb: https://git.kernel.org/tip/cf30ae726c011e0372fd4c2d588466c8b50a8907 Author: He Zhe <[email protected]> AuthorDate: Fri, 2 Aug 2019 16:29:51 +0800 Committer: Arnaldo Carvalho de Melo <[email protected]> CommitDate: Thu, 8 Aug 2019 15:41:10 -0300
perf ftrace: Fix failure to set cpumask when only one cpu is present 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 <[email protected]> Tested-by: Arnaldo Carvalho de Melo <[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: dc23103278c5 ("perf ftrace: Add support for -a and -C option") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[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 66d5a6658daf..019312810405 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);
