From patchwork Tue Sep 29 10:58:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 290952 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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 D377FC4741F for ; Tue, 29 Sep 2020 12:07:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F20720674 for ; Tue, 29 Sep 2020 12:07:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601381265; bh=ibA8gcQYmlotP6cznryHZI/OdgfEaEgutrgQue529Fg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OyXUHc8cxEpRZfnZszHPkOXbdEu6ZsWH4wi4IOBwuH51a3ngZyzab43YfLrSCHKes N5m+8jPWlR+a1NtuzmWe/kj3E8EAO70h1pZyzcm8zJax9xcp8LXYEIMq3B+o/DVcqU dDXGdEXOETe6sToBhb13ZTtnDdi/goMHVGl1YnPY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731713AbgI2MH0 (ORCPT ); Tue, 29 Sep 2020 08:07:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:52840 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730252AbgI2Lhg (ORCPT ); Tue, 29 Sep 2020 07:37:36 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E428423B6A; Tue, 29 Sep 2020 11:36:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379410; bh=ibA8gcQYmlotP6cznryHZI/OdgfEaEgutrgQue529Fg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZQbaKg+9uunL4a7ABpAC+KGSY3lN3SpVkhuSXplvG8D82FFrTPEV7lZ7ySCtcVTjH j5m8nd599XKUrL5xfsQMyS0ldivUW9SstGarCraehBMnCLoDRaw3QvK3/cpyfoJoMH lmKU6cRaY5NnP89niiqoRmvBkaDT8d5FbI4Yn1G8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qiujun Huang , Theodore Tso , Sasha Levin Subject: [PATCH 5.4 149/388] ext4: fix a data race at inode->i_disksize Date: Tue, 29 Sep 2020 12:58:00 +0200 Message-Id: <20200929110017.684772161@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929110010.467764689@linuxfoundation.org> References: <20200929110010.467764689@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Qiujun Huang [ Upstream commit dce8e237100f60c28cc66effb526ba65a01d8cb3 ] KCSAN find inode->i_disksize could be accessed concurrently. BUG: KCSAN: data-race in ext4_mark_iloc_dirty / ext4_write_end write (marked) to 0xffff8b8932f40090 of 8 bytes by task 66792 on cpu 0: ext4_write_end+0x53f/0x5b0 ext4_da_write_end+0x237/0x510 generic_perform_write+0x1c4/0x2a0 ext4_buffered_write_iter+0x13a/0x210 ext4_file_write_iter+0xe2/0x9b0 new_sync_write+0x29c/0x3a0 __vfs_write+0x92/0xa0 vfs_write+0xfc/0x2a0 ksys_write+0xe8/0x140 __x64_sys_write+0x4c/0x60 do_syscall_64+0x8a/0x2a0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8b8932f40090 of 8 bytes by task 14414 on cpu 1: ext4_mark_iloc_dirty+0x716/0x1190 ext4_mark_inode_dirty+0xc9/0x360 ext4_convert_unwritten_extents+0x1bc/0x2a0 ext4_convert_unwritten_io_end_vec+0xc5/0x150 ext4_put_io_end+0x82/0x130 ext4_writepages+0xae7/0x16f0 do_writepages+0x64/0x120 __writeback_single_inode+0x7d/0x650 writeback_sb_inodes+0x3a4/0x860 __writeback_inodes_wb+0xc4/0x150 wb_writeback+0x43f/0x510 wb_workfn+0x3b2/0x8a0 process_one_work+0x39b/0x7e0 worker_thread+0x88/0x650 kthread+0x1d4/0x1f0 ret_from_fork+0x35/0x40 The plain read is outside of inode->i_data_sem critical section which results in a data race. Fix it by adding READ_ONCE(). Signed-off-by: Qiujun Huang Link: https://lore.kernel.org/r/1582556566-3909-1-git-send-email-hqjagain@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index a284d99a1ee57..95a8a04c77dd3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5315,7 +5315,7 @@ static int ext4_do_update_inode(handle_t *handle, raw_inode->i_file_acl_high = cpu_to_le16(ei->i_file_acl >> 32); raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl); - if (ei->i_disksize != ext4_isize(inode->i_sb, raw_inode)) { + if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode)) { ext4_isize_set(raw_inode, ei->i_disksize); need_datasync = 1; }