Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755182AbdC1NYk (ORCPT ); Tue, 28 Mar 2017 09:24:40 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60080 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755044AbdC1Mko (ORCPT ); Tue, 28 Mar 2017 08:40:44 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tomas Winkler Subject: [PATCH 4.10 063/111] mei: fix deadlock on mei reset Date: Tue, 28 Mar 2017 14:30:49 +0200 Message-Id: <20170328122918.338367169@linuxfoundation.org> X-Mailer: git-send-email 2.12.1 In-Reply-To: <20170328122915.640228468@linuxfoundation.org> References: <20170328122915.640228468@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1730 Lines: 62 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tomas Winkler commit a733ded50b6ea846200073e7381a302df71e13b3 upstream. This patch fixes 'mei: synchronize irq before initiating a reset' The patch had introduced a deadlock between irq thread and mei_reset() as they are both holding the same device lock. ---> device_lock: mei_reset() <---- interrupt thread device_lock ---> synchornize_irq() wait on interrupt thread == (dead lock) The fix is to call synchronize_irq prior to call locked mei_reset function. Fixes: f302bb0de6ac (mei: synchronize irq before initiating a reset) Signed-off-by: Tomas Winkler Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/init.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/misc/mei/init.c +++ b/drivers/misc/mei/init.c @@ -124,8 +124,6 @@ int mei_reset(struct mei_device *dev) mei_clear_interrupts(dev); - mei_synchronize_irq(dev); - /* we're already in reset, cancel the init timer * if the reset was called due the hbm protocol error * we need to call it before hw start @@ -304,6 +302,9 @@ static void mei_reset_work(struct work_s container_of(work, struct mei_device, reset_work); int ret; + mei_clear_interrupts(dev); + mei_synchronize_irq(dev); + mutex_lock(&dev->device_lock); ret = mei_reset(dev); @@ -328,6 +329,9 @@ void mei_stop(struct mei_device *dev) mei_cancel_work(dev); + mei_clear_interrupts(dev); + mei_synchronize_irq(dev); + mutex_lock(&dev->device_lock); dev->dev_state = MEI_DEV_POWER_DOWN;