From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754859Ab2L1TsA (ORCPT ); Fri, 28 Dec 2012 14:48:00 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55164 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754171Ab2L1TR5 (ORCPT ); Fri, 28 Dec 2012 14:17:57 -0500 Message-Id: <20121228190357.660801084@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 28 Dec 2012 20:05:44 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Xiaotian Feng , Xiaotian Feng , James Bottomley , Jeff Garzik Subject: [ 134/173] [libata] fix Null pointer dereference on disk error In-Reply-To: <20121228190330.025298996@decadent.org.uk> X-SA-Exim-Connect-IP: 151.217.219.220 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiaotian Feng commit 26cd4d65deba587f3cf2329b6869ce02bcbe68ec upstream. Following oops were observed when disk error happened: [ 4272.896937] sd 0:0:0:0: [sda] Unhandled error code [ 4272.896939] sd 0:0:0:0: [sda] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK [ 4272.896942] sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 5a de a7 00 00 08 00 [ 4272.896951] end_request: I/O error, dev sda, sector 5955239 [ 4291.574947] BUG: unable to handle kernel NULL pointer dereference at (null) [ 4291.658305] IP: [] ahci_activity_show+0x1/0x40 [ 4291.730090] PGD 76dbbc067 PUD 6c4fba067 PMD 0 [ 4291.783408] Oops: 0000 [#1] SMP [ 4291.822100] last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/sw_activity [ 4291.934235] CPU 9 [ 4291.958301] Pid: 27942, comm: hwinfo ...... ata_scsi_find_dev could return NULL, so ata_scsi_activity_{show,store} should check if atadev is NULL. Signed-off-by: Xiaotian Feng Cc: James Bottomley Signed-off-by: Jeff Garzik Signed-off-by: Ben Hutchings --- drivers/ata/libata-scsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index a6df6a3..7c337e7 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -309,7 +309,8 @@ ata_scsi_activity_show(struct device *dev, struct device_attribute *attr, struct ata_port *ap = ata_shost_to_port(sdev->host); struct ata_device *atadev = ata_scsi_find_dev(ap, sdev); - if (ap->ops->sw_activity_show && (ap->flags & ATA_FLAG_SW_ACTIVITY)) + if (atadev && ap->ops->sw_activity_show && + (ap->flags & ATA_FLAG_SW_ACTIVITY)) return ap->ops->sw_activity_show(atadev, buf); return -EINVAL; } @@ -324,7 +325,8 @@ ata_scsi_activity_store(struct device *dev, struct device_attribute *attr, enum sw_activity val; int rc; - if (ap->ops->sw_activity_store && (ap->flags & ATA_FLAG_SW_ACTIVITY)) { + if (atadev && ap->ops->sw_activity_store && + (ap->flags & ATA_FLAG_SW_ACTIVITY)) { val = simple_strtoul(buf, NULL, 0); switch (val) { case OFF: case BLINK_ON: case BLINK_OFF: