Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753718Ab2HBI5Y (ORCPT ); Thu, 2 Aug 2012 04:57:24 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:38386 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750772Ab2HBI5W (ORCPT ); Thu, 2 Aug 2012 04:57:22 -0400 Message-ID: <1343897839.5073.7.camel@dabdike.int.hansenpartnership.com> Subject: Re: [PATCH] fix NULL-pointer dereference on scsi_run_queue From: James Bottomley To: Chanho Min Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Jens Axboe , Tejun Heo Date: Thu, 02 Aug 2012 09:57:19 +0100 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1037 Lines: 26 On Thu, 2012-08-02 at 17:41 +0900, Chanho Min wrote: > This patch is to fix a oops from a torn down device. When > scsi_run_queue process starved queues, scsi_request_fn can race with > scsi_remove_device. In this case, rarely, scsi_request_fn release the > last reference and set sdev->request_queue to NULL. It result in > NULL-pointer dereference when spin_unlock is tried with (NULL)-> > queue_lock. We need to add an extra reference to the device on both > sides of the __blk_run_queue to hold reference until scsi_request_fn > is finished. You need a recent kernel with this patch: commit 940f5d47e2f2e1fa00443921a0abf4822335b54d Author: Bart Van Assche Date: Fri Jun 29 15:34:26 2012 +0000 [SCSI] Avoid dangling pointer in scsi_requeue_command() James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/