From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932709Ab3GQWss (ORCPT ); Wed, 17 Jul 2013 18:48:48 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56191 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757469Ab3GQWso (ORCPT ); Wed, 17 Jul 2013 18:48:44 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jiang Liu , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 009/145] zram: avoid invalid memory access in zram_exit() Date: Wed, 17 Jul 2013 15:45:41 -0700 Message-Id: <1374101277-7915-10-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1374101277-7915-1-git-send-email-kamal@canonical.com> References: <1374101277-7915-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8.13.5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiang Liu commit 6030ea9b35971a4200062f010341ab832e878ac9 upstream. Memory for zram->disk object may have already been freed after returning from destroy_device(zram), then it's unsafe for zram_reset_device(zram) to access zram->disk again. We can't solve this bug by flipping the order of destroy_device(zram) and zram_reset_device(zram), that will cause deadlock issues to the zram sysfs handler. So fix it by holding an extra reference to zram->disk before calling destroy_device(zram). Signed-off-by: Jiang Liu Signed-off-by: Greg Kroah-Hartman [ luis: backported to 3.8: adjusted context ] Signed-off-by: Luis Henriques --- drivers/staging/zram/zram_drv.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 071e058..c9c1e0e 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -764,9 +764,11 @@ static void __exit zram_exit(void) for (i = 0; i < num_devices; i++) { zram = &zram_devices[i]; + get_disk(zram->disk); destroy_device(zram); if (zram->init_done) zram_reset_device(zram); + put_disk(zram->disk); } unregister_blkdev(zram_major, "zram"); -- 1.8.1.2