Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 63/68] perf ftrace: Fix failure to set cpumask when only one cpu is present | Date | Tue, 13 Aug 2019 22:15:41 -0400 |
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From: He Zhe <zhe.he@windriver.com>
[ 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.com 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 f42f228e88992..137955197ba8d 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -174,7 +174,7 @@ 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); -- 2.20.1
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