From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759378AbbIVRyM (ORCPT ); Tue, 22 Sep 2015 13:54:12 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42934 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933509AbbIVRyA (ORCPT ); Tue, 22 Sep 2015 13:54:00 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Alan Stern , James Bottomley , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 072/102] SCSI: Fix NULL pointer dereference in runtime PM Date: Tue, 22 Sep 2015 10:52:08 -0700 Message-Id: <1442944358-1248-73-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1442944358-1248-1-git-send-email-kamal@canonical.com> References: <1442944358-1248-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit 49718f0fb8c9af192b33d8af3a2826db04025371 upstream. The routines in scsi_rpm.c assume that if a runtime-PM callback is invoked for a SCSI device, it can only mean that the device's driver has asked the block layer to handle the runtime power management (by calling blk_pm_runtime_init(), which among other things sets q->dev). However, this assumption turns out to be wrong for things like the ses driver. Normally ses devices are not allowed to do runtime PM, but userspace can override this setting. If this happens, the kernel gets a NULL pointer dereference when blk_post_runtime_resume() tries to use the uninitialized q->dev pointer. This patch fixes the problem by calling the block layer's runtime-PM routines only if the device's driver really does have a runtime-PM callback routine. Since ses doesn't define any such callbacks, the crash won't occur. This fixes Bugzilla #101371. Signed-off-by: Alan Stern Reported-by: Stanisław Pitucha Reported-by: Ilan Cohen Tested-by: Ilan Cohen Reviewed-by: Johannes Thumshirn Signed-off-by: James Bottomley Signed-off-by: Kamal Mostafa --- drivers/scsi/scsi_pm.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c index 9e43ae1..e4b7998 100644 --- a/drivers/scsi/scsi_pm.c +++ b/drivers/scsi/scsi_pm.c @@ -217,15 +217,15 @@ static int sdev_runtime_suspend(struct device *dev) { const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; struct scsi_device *sdev = to_scsi_device(dev); - int err; + int err = 0; - err = blk_pre_runtime_suspend(sdev->request_queue); - if (err) - return err; - if (pm && pm->runtime_suspend) + if (pm && pm->runtime_suspend) { + err = blk_pre_runtime_suspend(sdev->request_queue); + if (err) + return err; err = pm->runtime_suspend(dev); - blk_post_runtime_suspend(sdev->request_queue, err); - + blk_post_runtime_suspend(sdev->request_queue, err); + } return err; } @@ -248,11 +248,11 @@ static int sdev_runtime_resume(struct device *dev) const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; int err = 0; - blk_pre_runtime_resume(sdev->request_queue); - if (pm && pm->runtime_resume) + if (pm && pm->runtime_resume) { + blk_pre_runtime_resume(sdev->request_queue); err = pm->runtime_resume(dev); - blk_post_runtime_resume(sdev->request_queue, err); - + blk_post_runtime_resume(sdev->request_queue, err); + } return err; } -- 1.9.1