ksmbd: fix uaf in smb20_oplock_break_ack

commit c698134 upstream.

drop reference after use opinfo.

Signed-off-by: luosili <rootlab@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/smb/server/smb2pdu.c

@@ -8128,10 +8128,10 @@ static void smb20_oplock_break_ack(struct ksmbd_work *work)
 		goto err_out;
 	}
 
-	opinfo_put(opinfo);
-	ksmbd_fd_put(work, fp);
 	opinfo->op_state = OPLOCK_STATE_NONE;
 	wake_up_interruptible_all(&opinfo->oplock_q);
+	opinfo_put(opinfo);
+	ksmbd_fd_put(work, fp);
 
 	rsp->StructureSize = cpu_to_le16(24);
 	rsp->OplockLevel = rsp_oplevel;