Messages in this thread | | | From | Arnaldo Carvalho de Melo <> | Date | Tue, 24 Mar 2020 09:50:01 -0300 | Subject | Re: [PATCH V2] perf cpumap: Fix snprintf overflow check |
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Em Tue, Mar 24, 2020 at 08:03:19AM +0100, Christophe JAILLET escreveu: > 'snprintf' returns the number of characters which would be generated for > the given input. > > If the returned value is *greater than* or equal to the buffer size, it > means that the output has been truncated. > > Fix the overflow test accordingling. y
You forgot to CC David and add this to your patch, which I did:
Suggested-by: David Laight <David.Laight@ACULAB.COM>
Ok?
- Arnaldo
> Fixes: 7780c25bae59f ("perf tools: Allow ability to map cpus to nodes easily") > Fixes: 92a7e1278005b ("perf cpumap: Add cpu__max_present_cpu()") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > V2: keep snprintf > modifiy the tests for truncated output > Update subject and description > --- > tools/perf/util/cpumap.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c > index 983b7388f22b..dc5c5e6fc502 100644 > --- a/tools/perf/util/cpumap.c > +++ b/tools/perf/util/cpumap.c > @@ -317,7 +317,7 @@ static void set_max_cpu_num(void) > > /* 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) { > + if (ret >= PATH_MAX) { > pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX); > goto out; > } > @@ -328,7 +328,7 @@ static void set_max_cpu_num(void) > > /* get the highest present cpu number for a sparse allocation */ > ret = snprintf(path, PATH_MAX, "%s/devices/system/cpu/present", mnt); > - if (ret == PATH_MAX) { > + if (ret >= PATH_MAX) { > pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX); > goto out; > } > @@ -356,7 +356,7 @@ static void set_max_node_num(void) > > /* get the highest possible cpu number for a sparse allocation */ > ret = snprintf(path, PATH_MAX, "%s/devices/system/node/possible", mnt); > - if (ret == PATH_MAX) { > + if (ret >= PATH_MAX) { > pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX); > goto out; > } > @@ -441,7 +441,7 @@ int cpu__setup_cpunode_map(void) > return 0; > > n = snprintf(path, PATH_MAX, "%s/devices/system/node", mnt); > - if (n == PATH_MAX) { > + if (n >= PATH_MAX) { > pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX); > return -1; > } > @@ -456,7 +456,7 @@ int cpu__setup_cpunode_map(void) > continue; > > n = snprintf(buf, PATH_MAX, "%s/%s", path, dent1->d_name); > - if (n == PATH_MAX) { > + if (n >= PATH_MAX) { > pr_err("sysfs path crossed PATH_MAX(%d) size\n", PATH_MAX); > continue; > } > -- > 2.20.1 >
--
- Arnaldo
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