From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9CDE2C433FF for ; Sat, 10 Aug 2019 20:49:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DC5E208C3 for ; Sat, 10 Aug 2019 20:49:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727092AbfHJUtr (ORCPT ); Sat, 10 Aug 2019 16:49:47 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54580 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726740AbfHJUn5 (ORCPT ); Sat, 10 Aug 2019 16:43:57 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hwYDS-00053i-Fm; Sat, 10 Aug 2019 21:43:54 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hwYDP-0003mZ-Ic; Sat, 10 Aug 2019 21:43:51 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "chenxiang" , "John Garry" , "Johannes Thumshirn" , "Ewan Milne" , "Dan Williams" , "Tomas Henzl" , "Martin K. Petersen" , "Hannes Reinecke" , "Christoph Hellwig" , "Jason Yan" Date: Sat, 10 Aug 2019 21:40:07 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 157/157] scsi: libsas: fix a race condition when smp task timeout In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 3.16.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jason Yan commit b90cd6f2b905905fb42671009dc0e27c310a16ae upstream. When the lldd is processing the complete sas task in interrupt and set the task stat as SAS_TASK_STATE_DONE, the smp timeout timer is able to be triggered at the same time. And smp_task_timedout() will complete the task wheter the SAS_TASK_STATE_DONE is set or not. Then the sas task may freed before lldd end the interrupt process. Thus a use-after-free will happen. Fix this by calling the complete() only when SAS_TASK_STATE_DONE is not set. And remove the check of the return value of the del_timer(). Once the LLDD sets DONE, it must call task->done(), which will call smp_task_done()->complete() and the task will be completed and freed correctly. Reported-by: chenxiang Signed-off-by: Jason Yan CC: John Garry CC: Johannes Thumshirn CC: Ewan Milne CC: Christoph Hellwig CC: Tomas Henzl CC: Dan Williams CC: Hannes Reinecke Reviewed-by: Hannes Reinecke Reviewed-by: John Garry Reviewed-by: Johannes Thumshirn Signed-off-by: Martin K. Petersen Signed-off-by: Ben Hutchings --- drivers/scsi/libsas/sas_expander.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -47,17 +47,16 @@ static void smp_task_timedout(unsigned l unsigned long flags; spin_lock_irqsave(&task->task_state_lock, flags); - if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) + if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) { task->task_state_flags |= SAS_TASK_STATE_ABORTED; + complete(&task->slow_task->completion); + } spin_unlock_irqrestore(&task->task_state_lock, flags); - - complete(&task->slow_task->completion); } static void smp_task_done(struct sas_task *task) { - if (!del_timer(&task->slow_task->timer)) - return; + del_timer(&task->slow_task->timer); complete(&task->slow_task->completion); }