Messages in this thread | | | Date | Fri, 2 Aug 2019 15:06:07 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 1/2] perf: Fix failure to set cpumask when only one cpu |
| |
On Fri, Aug 02, 2019 at 04:29:51PM +0800, zhe.he@windriver.com wrote: > From: He Zhe <zhe.he@windriver.com> > > 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 <zhe.he@windriver.com> > --- > 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 */
ugh.. why do we care about last_cpu value in here at all?
feels like using static buffer would be more reasonable
jirka
> > cpumask = malloc(mask_size); > -- > 2.7.4 >
| |