From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932640AbbAYTHc (ORCPT ); Sun, 25 Jan 2015 14:07:32 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:57698 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755353AbbAYSJ1 (ORCPT ); Sun, 25 Jan 2015 13:09:27 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Schwidefsky Subject: [PATCH 3.14 97/98] s390/3215: fix hanging console issue Date: Sun, 25 Jan 2015 10:07:55 -0800 Message-Id: <20150125180717.096396934@linuxfoundation.org> X-Mailer: git-send-email 2.2.2 In-Reply-To: <20150125180712.859646324@linuxfoundation.org> References: <20150125180712.859646324@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky commit 26d766c60f4ea08cd14f0f3435a6db3d6cc2ae96 upstream. The ccw_device_start in raw3215_start_io can fail. raw3215_try_io does not check if the request could be started and removes any pending timer. This can leave the system in a hanging state. Check for pending request after raw3215_start_io and start a timer if necessary. Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- drivers/s390/char/con3215.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) --- a/drivers/s390/char/con3215.c +++ b/drivers/s390/char/con3215.c @@ -288,12 +288,16 @@ static void raw3215_timeout(unsigned lon unsigned long flags; spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags); - if (raw->flags & RAW3215_TIMER_RUNS) { - del_timer(&raw->timer); - raw->flags &= ~RAW3215_TIMER_RUNS; - if (!(raw->port.flags & ASYNC_SUSPENDED)) { - raw3215_mk_write_req(raw); - raw3215_start_io(raw); + raw->flags &= ~RAW3215_TIMER_RUNS; + if (!(raw->port.flags & ASYNC_SUSPENDED)) { + raw3215_mk_write_req(raw); + raw3215_start_io(raw); + if ((raw->queued_read || raw->queued_write) && + !(raw->flags & RAW3215_WORKING) && + !(raw->flags & RAW3215_TIMER_RUNS)) { + raw->timer.expires = RAW3215_TIMEOUT + jiffies; + add_timer(&raw->timer); + raw->flags |= RAW3215_TIMER_RUNS; } } spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags); @@ -317,17 +321,15 @@ static inline void raw3215_try_io(struct (raw->flags & RAW3215_FLUSHING)) { /* execute write requests bigger than minimum size */ raw3215_start_io(raw); - if (raw->flags & RAW3215_TIMER_RUNS) { - del_timer(&raw->timer); - raw->flags &= ~RAW3215_TIMER_RUNS; - } - } else if (!(raw->flags & RAW3215_TIMER_RUNS)) { - /* delay small writes */ - raw->timer.expires = RAW3215_TIMEOUT + jiffies; - add_timer(&raw->timer); - raw->flags |= RAW3215_TIMER_RUNS; } } + if ((raw->queued_read || raw->queued_write) && + !(raw->flags & RAW3215_WORKING) && + !(raw->flags & RAW3215_TIMER_RUNS)) { + raw->timer.expires = RAW3215_TIMEOUT + jiffies; + add_timer(&raw->timer); + raw->flags |= RAW3215_TIMER_RUNS; + } } /*