From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 04/10] perf ftrace: Fix failure to set cpumask when only one cpu is present Date: Thu, 8 Aug 2019 15:53:52 -0300 Message-ID: <20190808185358.20125-5-acme@kernel.org> References: <20190808185358.20125-1-acme@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190808185358.20125-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar , Thomas Gleixner Cc: Jiri Olsa , Namhyung Kim , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, He Zhe , Arnaldo Carvalho de Melo , Alexander Shishkin , Alexey Budankov , Jiri Olsa , Kan Liang , Peter Zijlstra , Stephane Eranian List-Id: linux-perf-users.vger.kernel.org From: He Zhe 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 Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Alexey Budankov Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian 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.com Signed-off-by: Arnaldo Carvalho de Melo --- 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); -- 2.21.0