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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C07BFC43465 for ; Fri, 18 Sep 2020 02:10:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87A7D239E5 for ; Fri, 18 Sep 2020 02:10:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395005; bh=+pU0invXC4/YrAgQHq5Xiv0cJU+MIJEVjntsabr4JjU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TRrj7hF/9jkoL7qhSPXjA9iXmSawGpj3Lk18X2OW8sSWsS4STU4d9LxdPuhm2Pjig yuJfsNxil5WvPb8h5oMN+lNf++X6pfReif/imDvgXYuzj9BIArMlIoWeAPOjr3NTxQ RVlMex0oz3KyI/YalvHy32IfCQbQXxoryhpDrMfQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728395AbgIRCKE (ORCPT ); Thu, 17 Sep 2020 22:10:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:33558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728382AbgIRCKA (ORCPT ); Thu, 17 Sep 2020 22:10:00 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DE8CA235F9; Fri, 18 Sep 2020 02:09:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394999; bh=+pU0invXC4/YrAgQHq5Xiv0cJU+MIJEVjntsabr4JjU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cbPHDx2VBBDmQrKhk+l+ruRmvqG7kSgsep75tulNxz5FZrsu9ws1fM4WQypTdJs5e tgLoTBZmYKq5LGwEchkJH6zJkwdv81BE1hQ863mbYSsgKIBNjSw+J78aHxicF75nG4 Z+LAIGgo6F5d6y4bsPrDxY+q1i2s1tDrzh0xs9cc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Qiujun Huang , Theodore Ts'o , Sasha Levin , linux-ext4@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 097/206] ext4: fix a data race at inode->i_disksize Date: Thu, 17 Sep 2020 22:06:13 -0400 Message-Id: <20200918020802.2065198-97-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020802.2065198-1-sashal@kernel.org> References: <20200918020802.2065198-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@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 cd833f4e64ef1..52be4c9650241 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; } -- 2.25.1