Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753340Ab3FFQLT (ORCPT ); Thu, 6 Jun 2013 12:11:19 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:64619 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753232Ab3FFQLP (ORCPT ); Thu, 6 Jun 2013 12:11:15 -0400 From: Jiang Liu To: Greg Kroah-Hartman , Nitin Gupta , Minchan Kim , Jerome Marchand Cc: Jiang Liu , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v3 06/10] zram: protect sysfs handler from invalid memory access Date: Fri, 7 Jun 2013 00:07:27 +0800 Message-Id: <1370534851-26056-7-git-send-email-jiang.liu@huawei.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1370534851-26056-1-git-send-email-jiang.liu@huawei.com> References: <1370534851-26056-1-git-send-email-jiang.liu@huawei.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1283 Lines: 40 Use zram->init_lock to protect access to zram->meta, otherwise it may cause invalid memory access if zram->meta has been freed by zram_reset_device(). This issue may be triggered by: Thread 1: while true; do cat mem_used_total; done Thread 2: while true; do echo 8M > disksize; echo 1 > reset; done Signed-off-by: Jiang Liu Acked-by: Minchan Kim Cc: stable@vger.kernel.org --- drivers/staging/zram/zram_sysfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/zram/zram_sysfs.c b/drivers/staging/zram/zram_sysfs.c index e6a929d..dc76a3d 100644 --- a/drivers/staging/zram/zram_sysfs.c +++ b/drivers/staging/zram/zram_sysfs.c @@ -188,8 +188,10 @@ static ssize_t mem_used_total_show(struct device *dev, struct zram *zram = dev_to_zram(dev); struct zram_meta *meta = zram->meta; + down_read(&zram->init_lock); if (zram->init_done) val = zs_get_total_size_bytes(meta->mem_pool); + up_read(&zram->init_lock); return sprintf(buf, "%llu\n", val); } -- 1.8.1.2 -- 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/