[PATCH] orangefs: Fix possible NULL deference in orangefs_mount

[Su Hui <suhui@nfschina.com>]

scripts/coccinelle/null/deref_null.cocci complains:
fs/orangefs/super.c:584:18-25: ERROR:
ORANGEFS_SB ( sb ) is NULL but dereferenced.

When memory allocation for orangefs_sb_info_s fails, ORANGEFS_SB(sb)
is NULL and ORANGEFS_SB(sb)->no_list will result in NULL deference.
Add a judgement to fix this NULL deference problem.

Fixes: ac2c63757f4f ("orangefs: Fix sb refcount leak when allocate sb info failed.")
Signed-off-by: Su Hui <suhui@nfschina.com>
---
 fs/orangefs/super.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index 5254256a224d..c056c86e2482 100644
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -581,7 +581,8 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
 
 free_sb_and_op:
 	/* Will call orangefs_kill_sb with sb not in list. */
-	ORANGEFS_SB(sb)->no_list = 1;
+	if (ORANGEFS_SB(sb))
+		ORANGEFS_SB(sb)->no_list = 1;
 	/* ORANGEFS_VFS_OP_FS_UMOUNT is done by orangefs_kill_sb. */
 	deactivate_locked_super(sb);
 free_op:
-- 
2.30.2