perf cpumap: Fix snprintf overflow check (d74b181a) · Commits · 戴 / test

'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: ("perf tools: Allow ability to map cpus to nodes easily") Fixes: ("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>

tools/perf/util/cpumap.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -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;
		}

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