cpufreq: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq_stats.c

@@ -90,35 +90,35 @@ static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 	if (policy->fast_switch_enabled)
 		return 0;
 
-	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
-	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "         : ");
 	for (i = 0; i < stats->state_num; i++) {
 		if (len >= PAGE_SIZE)
 			break;
-		len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%9u ",
 				stats->freq_table[i]);
 	}
 	if (len >= PAGE_SIZE)
 		return PAGE_SIZE;
 
-	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+	len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
 
 	for (i = 0; i < stats->state_num; i++) {
 		if (len >= PAGE_SIZE)
 			break;
 
-		len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
+		len += scnprintf(buf + len, PAGE_SIZE - len, "%9u: ",
 				stats->freq_table[i]);
 
 		for (j = 0; j < stats->state_num; j++) {
 			if (len >= PAGE_SIZE)
 				break;
-			len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
+			len += scnprintf(buf + len, PAGE_SIZE - len, "%9u ",
 					stats->trans_table[i*stats->max_state+j]);
 		}
 		if (len >= PAGE_SIZE)
 			break;
-		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+		len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
 	}
 
 	if (len >= PAGE_SIZE) {