From: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Date: Sun, 26 Jan 2025 06:01:25 +0000 (+0530)
Subject: config: Fix data race reported in cgroup_config_insert_into_mount_table
X-Git-Tag: v3.2.0~17
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b4bc68c302acdb44540e521093bd47b5d48688f8;p=thirdparty%2Flibcgroup.git

config: Fix data race reported in cgroup_config_insert_into_mount_table

Fix the following data race issue reported by Coverity:

CID 465888: (#1 of 1): Check of thread-shared field evades lock
acquisition (LOCK_EVASION):

"The data guarded by this critical section may be read while in an
inconsistent state or modified by multiple racing threads.

In cgroup_config_insert_into_mount_table: Checking the value of a
thread-shared field outside of a locked region to determine if a locked
operation involving that thread shared field has completed."

Fix it by moving the config_table_index value check too under the
config_table_lock.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
---

diff --git a/src/config.c b/src/config.c
index b47a44d6..afaf9aad 100644
--- a/src/config.c
+++ b/src/config.c
@@ -551,11 +551,13 @@ int cgroup_config_insert_into_mount_table(char *name, char *mount_point)
 {
 	int i;
 
-	if (config_table_index >= CG_CONTROLLER_MAX)
-		return 0;
-
 	pthread_rwlock_wrlock(&config_table_lock);
 
+	if (config_table_index >= CG_CONTROLLER_MAX) {
+		pthread_rwlock_unlock(&config_table_lock);
+		return 0;
+	}
+
 	/* Merge controller names with the same mount point */
 	for (i = 0; i < config_table_index; i++) {
 		if (strcmp(config_mount_table[i].mount.path, mount_point) == 0) {