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perf cpumap: Fix snprintf overflow check 

'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 accordingly.

Fixes: 7780c25bae ("perf tools: Allow ability to map cpus to nodes easily")
Fixes: 92a7e12780 ("perf cpumap: Add cpu__max_present_cpu()")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Suggested-by: David Laight <David.Laight@ACULAB.COM>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: He Zhe <zhe.he@windriver.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-janitors@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200324070319.10901-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
alistair/sensors
Christophe JAILLET 2020-03-24 08:03:19 +01:00 committed by Arnaldo Carvalho de Melo
parent 956a78356c
commit d74b181a02
1 changed files with 5 additions and 5 deletions
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10
tools/perf/util/cpumap.c
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@ -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;
}