On Mon, Mar 23, 2020 at 01:08:47PM +0100, Christophe JAILLET wrote:
> Le 23/03/2020 à 12:03, Dan Carpenter a écrit :
> > On Sun, Mar 22, 2020 at 06:25:23PM +0100, Christophe JAILLET wrote:
> > > 'scnprintf' returns the number of characters written in the output buffer
> > > excluding the trailing '\0', instead of the number of characters which
> > > would be generated for the given input.
> > >
> > > Both function return a number of characters, excluding the trailing '\0'.
> > > So comparaison to check if it overflows, should be done against max_size-1.
> > > Comparaison against max_size can never match.
> > >
> > > Fixes: 7780c25bae59f ("perf tools: Allow ability to map cpus to nodes easily")
> > > Fixes: a24020e6b7cf6 ("perf tools: Change cpu_map__fprintf output")
> > > Fixes: 92a7e1278005b ("perf cpumap: Add cpu__max_present_cpu()")
> > > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > > ---
> > > tools/perf/util/cpumap.c | 39 ++++++++++++++++++++-------------------
> > > 1 file changed, 20 insertions(+), 19 deletions(-)
> > >
> > > diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
> > > index 983b7388f22b..b87e7ef4d130 100644
> > > --- a/tools/perf/util/cpumap.c
> > > +++ b/tools/perf/util/cpumap.c
> > > @@ -316,8 +316,8 @@ static void set_max_cpu_num(void)
> > > goto out;
> > > /* get the highest possible cpu number for a sparse allocation */
> > > - ret = snprintf(path, PATH_MAX, "%s/devices/system/cpu/possible", mnt);
> > > - if (ret == PATH_MAX) {
> > > + ret = scnprintf(path, PATH_MAX, "%s/devices/system/cpu/possible", mnt);
> > > + if (ret == PATH_MAX-1) {
> > This should be a static analysis warning.
> >
> > But isn't this stuff userspace? I can't figure out how to compile it on
> > Debian so I'm not sure. There is no scnprintf() in user space.
> >
> > regards,
> > dan carpenter
>
> I compiled it with:
>
> make tools/perf
>
Ah. You're absolutely right. My bad. Sorry for that.
I was doing "cd tools/perf; make" and it told me to install glibc-dev.
regards,
dan carpenter
