Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752344Ab3JaL5R (ORCPT ); Thu, 31 Oct 2013 07:57:17 -0400 Received: from mail-pb0-f51.google.com ([209.85.160.51]:61310 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751817Ab3JaL44 (ORCPT ); Thu, 31 Oct 2013 07:56:56 -0400 From: Rashika Kheria To: opw-kernel@googlegroups.com, Minchan Kim , Greg Kroah-Hartman , Jiang Liu , Nitin Gupta , Jerome Marchand , linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Subject: [PATCH v9 1/2] Staging: zram: Fix access of NULL pointer Date: Thu, 31 Oct 2013 17:26:46 +0530 Message-Id: <3d7e050910ca994862e7880b4bd3681267681b56.1383220461.git.rashika.kheria@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <20131019110539.GA25167@gmail.com> References: <20131019110539.GA25167@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1578 Lines: 49 This patch fixes the bug in reset_store caused by accessing NULL pointer. The bdev gets its value from bdget_disk() which could fail when memory pressure is severe and hence can return NULL because allocation of inode in bdget could fail. Hence, this patch introduces a check for bdev to prevent reference to a NULL pointer in the later part of the code. It also removes unnecessary check of bdev for fsync_bdev(). Cc: stable@vger.kernel.org Acked-by: Jerome Marchand Signed-off-by: Rashika Kheria --- drivers/staging/zram/zram_drv.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 2c4ed52..012ba15 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -648,6 +648,9 @@ static ssize_t reset_store(struct device *dev, zram = dev_to_zram(dev); bdev = bdget_disk(zram->disk, 0); + if (!bdev) + return -ENOMEM; + /* Do not reset an active device! */ if (bdev->bd_holders) return -EBUSY; @@ -660,8 +663,7 @@ static ssize_t reset_store(struct device *dev, return -EINVAL; /* Make sure all pending I/O is finished */ - if (bdev) - fsync_bdev(bdev); + fsync_bdev(bdev); zram_reset_device(zram, true); return len; -- 1.7.9.5 -- 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/