From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92CA6CA9EAF for ; Sun, 27 Oct 2019 13:46:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56BA021850 for ; Sun, 27 Oct 2019 13:46:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572183970; bh=/DcQHiygesIWnEpYAdMh0vC+TfmG4tI8etRWMdBFvM0=; h=Subject:To:Cc:From:Date:List-ID:From; b=BIuR2ieDJ+96F7x4O+i3uJ4zeO8nvl6+wh6znbAKF0MvW6YJFXjyrMEpEaLPxGkEy JVfRgn+kLo6lu7x7aA3Zq1f6dgkK00DjbYBPYXhAJcMATsZqZTcNeTTgFLJ92GbY8A dcwb5HlA7IAXrmeaTK0QfArSFGsoT6nVkf/4HRow= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726706AbfJ0NqK (ORCPT ); Sun, 27 Oct 2019 09:46:10 -0400 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:60509 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726687AbfJ0NqJ (ORCPT ); Sun, 27 Oct 2019 09:46:09 -0400 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id 3A2C421BA9; Sun, 27 Oct 2019 09:46:09 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute6.internal (MEProxy); Sun, 27 Oct 2019 09:46:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=CVl9aN rgBhixYPpeE7yCGyT+Xry1clWISwJ1dXTyo8s=; b=W+wEdNjOt1bSYdDwye1tJV bhw6T2KAPWljAdiP/N9+Vs5C2FJvyu/RZVnyvm/FY1XiGSP/tcQmRhOjdtxSoQBs 76oCQE3uftI6VlFPIbD+CA/NrGAiGoogHc29FKFMNg2sCjwAgbscXCoHqXR7qSLB xL0FrvlKDzzH6K5njWdugK60n4zGGOcvbfl1ciDkRKCQQxd7pvVIrXLHuSu+adQL 3vZ2LKVwNGYR04fJFgONBVwam4oV1bOksO/DNjgAWC8IHSmGQzT+jceeewLC/BTQ J4wkZutPO75d6JOf9+yfmYXscQXu7+CWEvHe5BySPXFBnj3SXceJ5Ik/n6MZRm/A == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedufedrleejgdehkecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeejjedrvdeguddrvddvle drvdefvdenucfrrghrrghmpehmrghilhhfrhhomhepghhrvghgsehkrhhorghhrdgtohhm necuvehluhhsthgvrhfuihiivgepge X-ME-Proxy: Received: from localhost (unknown [77.241.229.232]) by mail.messagingengine.com (Postfix) with ESMTPA id 3A8138005B; Sun, 27 Oct 2019 09:46:08 -0400 (EDT) Subject: FAILED: patch "[PATCH] zram: fix race between backing_dev_show and backing_dev_store" failed to apply to 4.14-stable tree To: chenwandun@huawei.com, akpm@linux-foundation.org, axboe@kernel.dk, minchan@kernel.org, sergey.senozhatsky.work@gmail.com, stable@vger.kernel.org, torvalds@linux-foundation.org Cc: From: Date: Sun, 27 Oct 2019 14:46:06 +0100 Message-ID: <15721839663649@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f7daefe4231e57381d92c2e2ad905a899c28e402 Mon Sep 17 00:00:00 2001 From: Chenwandun Date: Fri, 18 Oct 2019 20:20:14 -0700 Subject: [PATCH] zram: fix race between backing_dev_show and backing_dev_store CPU0: CPU1: backing_dev_show backing_dev_store ...... ...... file = zram->backing_dev; down_read(&zram->init_lock); down_read(&zram->init_init_lock) file_path(file, ...); zram->backing_dev = backing_dev; up_read(&zram->init_lock); up_read(&zram->init_lock); gets the value of zram->backing_dev too early in backing_dev_show, which resultin the value being NULL at the beginning, and not NULL later. backtrace: d_path+0xcc/0x174 file_path+0x10/0x18 backing_dev_show+0x40/0xb4 dev_attr_show+0x20/0x54 sysfs_kf_seq_show+0x9c/0x10c kernfs_seq_show+0x28/0x30 seq_read+0x184/0x488 kernfs_fop_read+0x5c/0x1a4 __vfs_read+0x44/0x128 vfs_read+0xa0/0x138 SyS_read+0x54/0xb4 Link: http://lkml.kernel.org/r/1571046839-16814-1-git-send-email-chenwandun@huawei.com Signed-off-by: Chenwandun Acked-by: Minchan Kim Cc: Sergey Senozhatsky Cc: Jens Axboe Cc: [4.14+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index d58a359a6622..4285e75e52c3 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -413,13 +413,14 @@ static void reset_bdev(struct zram *zram) static ssize_t backing_dev_show(struct device *dev, struct device_attribute *attr, char *buf) { + struct file *file; struct zram *zram = dev_to_zram(dev); - struct file *file = zram->backing_dev; char *p; ssize_t ret; down_read(&zram->init_lock); - if (!zram->backing_dev) { + file = zram->backing_dev; + if (!file) { memcpy(buf, "none\n", 5); up_read(&zram->init_lock); return 5;