[PATCH v2] posix_acl: fix memleak when set posix acl.

[Zhang Xiaoxu <zhangxiaoxu5@huawei.com>]

When set posix acl, it maybe call posix_acl_update_mode in some
filesystem, eg. ext4. It may set acl to NULL, so, we can't free
the acl which allocated in posix_acl_xattr_set.

Use an temp value to store the acl address for posix_acl_release.

Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
---
 fs/posix_acl.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 84ad1c90d535..0a359d06274c 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -882,7 +882,7 @@ posix_acl_xattr_set(const struct xattr_handler *handler,
 		    const char *name, const void *value,
 		    size_t size, int flags)
 {
-	struct posix_acl *acl = NULL;
+	struct posix_acl *acl = NULL, *p = NULL;
 	int ret;
 
 	if (value) {
@@ -890,8 +890,15 @@ posix_acl_xattr_set(const struct xattr_handler *handler,
 		if (IS_ERR(acl))
 			return PTR_ERR(acl);
 	}
+
+	/*
+	 * when call set_posix_acl, posix_acl_update_mode may set acl
+	 * to NULL,use temporary variables p for posix_acl_release.
+	 */
+	p = acl;
 	ret = set_posix_acl(inode, handler->flags, acl);
-	posix_acl_release(acl);
+
+	posix_acl_release(p);
 	return ret;
 }
 
-- 
2.17.2