Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967747Ab3HICLW (ORCPT ); Thu, 8 Aug 2013 22:11:22 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55784 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967654Ab3HIB7L (ORCPT ); Thu, 8 Aug 2013 21:59:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiang Liu Subject: [ 060/102] zram: avoid invalid memory access in zram_exit() Date: Thu, 8 Aug 2013 18:57:36 -0700 Message-Id: <20130809015024.373031068@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130809015010.208118575@linuxfoundation.org> References: <20130809015010.208118575@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1408 Lines: 46 3.10-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 --- drivers/staging/zram/zram_drv.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -727,8 +727,10 @@ 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); } unregister_blkdev(zram_major, "zram"); -- 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/