From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755842Ab3HLGOD (ORCPT ); Mon, 12 Aug 2013 02:14:03 -0400 Received: from lgeamrelo01.lge.com ([156.147.1.125]:52098 "EHLO LGEAMRELO01.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754164Ab3HLGOA (ORCPT ); Mon, 12 Aug 2013 02:14:00 -0400 X-AuditID: 9c93017d-b7cdfae0000026c0-58-52087d269269 From: Minchan Kim To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Minchan Kim , Nitin Gupta , Jiang Liu , stable@vger.kernel.org Subject: [PATCH] zram: fix invalid memory access Date: Mon, 12 Aug 2013 15:13:55 +0900 Message-Id: <1376288036-14628-1-git-send-email-minchan@kernel.org> X-Mailer: git-send-email 1.7.9.5 X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [1] tried to fix invalid memory access on zram->disk but it didn't fix properly because get_disk failed during module exit path. Actually, we don't need to reset zram->disk's capacity to zero in module exit path so that this patch introduces new argument "reset_capacity" on zram_reset_divice and it only reset it when reset_store is called. [1] 6030ea9b, zram: avoid invalid memory access in zram_exit() Cc: Nitin Gupta Cc: Jiang Liu Cc: stable@vger.kernel.org Signed-off-by: Minchan Kim --- drivers/staging/zram/zram_drv.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 7ebf91d..ebf9d6c 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -523,7 +523,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, return ret; } -static void zram_reset_device(struct zram *zram) +static void zram_reset_device(struct zram *zram, bool reset_capacity) { size_t index; struct zram_meta *meta; @@ -552,7 +552,8 @@ static void zram_reset_device(struct zram *zram) memset(&zram->stats, 0, sizeof(zram->stats)); zram->disksize = 0; - set_capacity(zram->disk, 0); + if (reset_capacity) + set_capacity(zram->disk, 0); up_write(&zram->init_lock); } @@ -636,7 +637,7 @@ static ssize_t reset_store(struct device *dev, if (bdev) fsync_bdev(bdev); - zram_reset_device(zram); + zram_reset_device(zram, true); return len; } @@ -903,10 +904,12 @@ static void __exit zram_exit(void) for (i = 0; i < num_devices; i++) { zram = &zram_devices[i]; - get_disk(zram->disk); destroy_device(zram); - zram_reset_device(zram); - put_disk(zram->disk); + /* + * Shouldn't access zram->disk after destroy_device + * because destroy_device already released zram->disk. + */ + zram_reset_device(zram, false); } unregister_blkdev(zram_major, "zram"); -- 1.7.9.5