fix oops in fs/9p late mount failure
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>
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 14a8644..69357c0 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -188,7 +188,8 @@
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);