From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752007AbcBLRKH (ORCPT ); Fri, 12 Feb 2016 12:10:07 -0500 Received: from mga04.intel.com ([192.55.52.120]:31443 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751003AbcBLRKE (ORCPT ); Fri, 12 Feb 2016 12:10:04 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,436,1449561600"; d="scan'208";a="882992054" From: Alexander Shishkin To: Greg KH Cc: Mathieu Poirier , Chunyan Zhang , laurent.fert@intel.com, yann.fouassier@intel.com, linux-kernel@vger.kernel.org, Alexander Shishkin Subject: [QUEUED v20160212 14/19] stm class: Fix unlocking braino in the error path Date: Fri, 12 Feb 2016 19:00:30 +0200 Message-Id: <1455296435-17362-15-git-send-email-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1455296435-17362-1-git-send-email-alexander.shishkin@linux.intel.com> References: <1455296435-17362-1-git-send-email-alexander.shishkin@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If an illegal attempt is made to unlink stm source device from an stm device, the stm device's link spinlock mistakenly remains locked. While this really shouldn't happen (there's a warning in place), the locking should remain in order so that we can still recover from this situation if it indeed does happen. This patch unifies the unlocking in the exit path of __stm_source_link_drop() to fix this. Reported-by: Laurent Fert Signed-off-by: Alexander Shishkin --- drivers/hwtracing/stm/core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 385db65994..fb5a6a582b 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -816,10 +816,8 @@ static void __stm_source_link_drop(struct stm_source_device *src, spin_lock(&stm->link_lock); spin_lock(&src->link_lock); link = srcu_dereference_check(src->link, &stm_source_srcu, 1); - if (WARN_ON_ONCE(link != stm)) { - spin_unlock(&src->link_lock); - return; - } + if (WARN_ON_ONCE(link != stm)) + goto unlock; stm_output_free(link, &src->output); list_del_init(&src->link_entry); @@ -827,6 +825,7 @@ static void __stm_source_link_drop(struct stm_source_device *src, stm_put_device(link); rcu_assign_pointer(src->link, NULL); +unlock: spin_unlock(&src->link_lock); spin_unlock(&stm->link_lock); } -- 2.7.0