From: Michael Jeanson <mjeanson@efficios.com>
Date: Wed, 27 Jul 2022 14:54:53 +0000 (-0400)
Subject: fix: removed accidental VLA in _get_num_possible_cpus()
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=feac72042ef1572189d4280a4f151ce049ac2b1e;p=lttng-ust.git

fix: removed accidental VLA in _get_num_possible_cpus()

The LTTNG_UST_PAGE_SIZE define can either point to a literal value or
the sysconf() function making buf[] a VLA. Replace this by a
cpumask specifc define that will always be a literal value.

Change-Id: I8d329f314878e8018939f979861918969e3ec8ac
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/src/common/smp.c b/src/common/smp.c
index d7ba23c4..980947cf 100644
--- a/src/common/smp.c
+++ b/src/common/smp.c
@@ -10,13 +10,13 @@
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <unistd.h>
 #include <pthread.h>
 #include <stdlib.h>
 
 #include <urcu/compiler.h>
 
-#include "common/align.h"
 #include "common/logging.h"
 #include "common/smp.h"
 
@@ -190,11 +190,10 @@ error:
 static void _get_num_possible_cpus(void)
 {
 	int ret;
-	int buf_len = LTTNG_UST_PAGE_SIZE;
-	char buf[buf_len];
+	char buf[LTTNG_UST_CPUMASK_SIZE];
 
 	/* Get the possible cpu mask from sysfs, fallback to sysconf. */
-	ret = get_possible_cpu_mask_from_sysfs((char *) &buf, buf_len);
+	ret = get_possible_cpu_mask_from_sysfs((char *) &buf, LTTNG_UST_CPUMASK_SIZE);
 	if (ret <= 0)
 		goto fallback;
 
diff --git a/src/common/smp.h b/src/common/smp.h
index b6dd5707..51fbd2d7 100644
--- a/src/common/smp.h
+++ b/src/common/smp.h
@@ -7,6 +7,8 @@
 #ifndef _UST_COMMON_SMP_H
 #define _UST_COMMON_SMP_H
 
+#define LTTNG_UST_CPUMASK_SIZE 4096
+
 /*
  * Get the CPU possible mask string from sysfs.
  *