From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 25 Jan 2010 11:16:19 +0000 (-0500)
Subject: fix oops in fs/9p late mount failure
X-Git-Tag: firefly_0821_release~11625^2~146
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=26d2257801281a5bd2833d8f22cebead57a4b4c6;p=firefly-linux-kernel-4.4.55.git

fix oops in fs/9p late mount failure

commit 083c73c253c23c20359a344dfe1198ea628e6259 upstream.

if 9P ->get_sb() fails late (at root inode or root dentry
allocation), we'll hit its ->kill_sb() with NULL ->s_root

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 14a86448572c..69357c0d9899 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -188,7 +188,8 @@ static void v9fs_kill_super(struct super_block *s)
 
 	P9_DPRINTK(P9_DEBUG_VFS, " %p\n", s);
 
-	v9fs_dentry_release(s->s_root);	/* clunk root */
+	if (s->s_root)
+		v9fs_dentry_release(s->s_root);	/* clunk root */
 
 	kill_anon_super(s);