From patchwork Mon Sep 3 03:33:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ronnie Sahlberg X-Patchwork-Id: 965185 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 423bDR4btcz9ryn for ; Mon, 3 Sep 2018 13:34:15 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725828AbeICHw1 (ORCPT ); Mon, 3 Sep 2018 03:52:27 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:35654 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725762AbeICHw0 (ORCPT ); Mon, 3 Sep 2018 03:52:26 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6ED10402243B; Mon, 3 Sep 2018 03:34:14 +0000 (UTC) Received: from test1135.test.redhat.com (vpn2-54-85.bne.redhat.com [10.64.54.85]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7BB832156889; Mon, 3 Sep 2018 03:34:13 +0000 (UTC) From: Ronnie Sahlberg To: linux-cifs Cc: Steve French Subject: [PATCH 11/12] cifs: add a warning if we try to to dequeue a deleted mid Date: Mon, 3 Sep 2018 13:33:51 +1000 Message-Id: <20180903033352.29586-12-lsahlber@redhat.com> In-Reply-To: <20180903033352.29586-1-lsahlber@redhat.com> References: <20180903033352.29586-1-lsahlber@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Mon, 03 Sep 2018 03:34:14 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Mon, 03 Sep 2018 03:34:14 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'lsahlber@redhat.com' RCPT:'' Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org cifs_delete_mid() is called once we are finished handling a mid and we expect no more work done on this mid. Add a warning if someone tries to dequeue a mid that has already been flagged to be deleted. Also change list_del() to list_del_init() so that if we have similar bugs resurface in the future we will not oops. Signed-off-by: Ronnie Sahlberg --- fs/cifs/cifsglob.h | 1 + fs/cifs/connect.c | 10 +++++++++- fs/cifs/transport.c | 3 ++- 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 0c9ab62c3df4..9dcaed031843 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1553,6 +1553,7 @@ static inline void free_dfs_info_array(struct dfs_info3_param *param, /* Flags */ #define MID_WAIT_CANCELLED 1 /* Cancelled while waiting for response */ +#define MID_DELETED 2 /* Mid has been dequeued/deleted */ /* Types of response buffer returned from SendReceive2 */ #define CIFS_NO_BUFFER 0 /* Response buffer not returned */ diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 7aa08dba4719..e9d64c92b8da 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -659,7 +659,15 @@ dequeue_mid(struct mid_q_entry *mid, bool malformed) mid->mid_state = MID_RESPONSE_RECEIVED; else mid->mid_state = MID_RESPONSE_MALFORMED; - list_del_init(&mid->qhead); + /* + * Trying to handle/dequeue a mid after the send_recv() + * function has finished processing it is a bug. + */ + if (mid->mid_flags & MID_DELETED) + printk_once(KERN_WARNING + "trying to dequeue a deleted mid\n"); + else + list_del_init(&mid->qhead); spin_unlock(&GlobalMid_Lock); } diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 78f96fa3d7d9..9cc9a127749e 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -142,7 +142,8 @@ void cifs_delete_mid(struct mid_q_entry *mid) { spin_lock(&GlobalMid_Lock); - list_del(&mid->qhead); + list_del_init(&mid->qhead); + mid->mid_flags |= MID_DELETED; spin_unlock(&GlobalMid_Lock); DeleteMidQEntry(mid);