Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756332Ab0LMAFD (ORCPT ); Sun, 12 Dec 2010 19:05:03 -0500 Received: from one.firstfloor.org ([213.235.205.2]:36378 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755313Ab0LLXrX (ORCPT ); Sun, 12 Dec 2010 18:47:23 -0500 From: Andi Kleen References: <201012131244.547034648@firstfloor.org> In-Reply-To: <201012131244.547034648@firstfloor.org> To: tj@kernel.org, jgarzik@redhat.com, gregkh@suse.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org Subject: [PATCH] [139/223] libata: fix NULL sdev dereference race in atapi_qc_complete() Message-Id: <20101212234721.B0F8EB27BF@basil.firstfloor.org> Date: Mon, 13 Dec 2010 00:47:21 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1581 Lines: 42 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Tejun Heo commit 2a5f07b5ec098edc69e05fdd2f35d3fbb1235723 upstream. SCSI commands may be issued between __scsi_add_device() and dev->sdev assignment, so it's unsafe for ata_qc_complete() to dereference dev->sdev->locked without checking whether it's NULL or not. Fix it. Signed-off-by: Tejun Heo Signed-off-by: Jeff Garzik Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- drivers/ata/libata-scsi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) Index: linux/drivers/ata/libata-scsi.c =================================================================== --- linux.orig/drivers/ata/libata-scsi.c +++ linux/drivers/ata/libata-scsi.c @@ -2577,8 +2577,11 @@ static void atapi_qc_complete(struct ata * * If door lock fails, always clear sdev->locked to * avoid this infinite loop. + * + * This may happen before SCSI scan is complete. Make + * sure qc->dev->sdev isn't NULL before dereferencing. */ - if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL) + if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL && qc->dev->sdev) qc->dev->sdev->locked = 0; qc->scsicmd->result = SAM_STAT_CHECK_CONDITION; -- 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/