reiserfs: only call unlock_new_inode() if I_NEW

unlock_new_inode() is only meant to be called after a new inode has
already been inserted into the hash table.  But reiserfs_new_inode() can
call it even before it has inserted the inode, triggering the WARNING in
unlock_new_inode().  Fix this by only calling unlock_new_inode() if the
inode has the I_NEW flag set, indicating that it's in the table.

This addresses the syzbot report "WARNING in unlock_new_inode"
(https://syzkaller.appspot.com/bug?extid=187510916eb6a14598f7).

Link: https://lore.kernel.org/r/20200628070057.820213-1-ebiggers@kernel.org
Reported-by: syzbot+187510916eb6a14598f7@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 1509775..e3af44c 100644 (file)
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -2163,7 +2163,8 @@ out_end_trans:
 out_inserted_sd:
        clear_nlink(inode);
        th->t_trans_id = 0;     /* so the caller can't use this handle later */
-       unlock_new_inode(inode); /* OK to do even if we hadn't locked it */
+       if (inode->i_state & I_NEW)
+               unlock_new_inode(inode);
        iput(inode);
        return err;
 }