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=-1.0 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 8B014C2D0F6 for ; Wed, 13 May 2020 02:45:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A82520714 for ; Wed, 13 May 2020 02:45:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726647AbgEMCpz convert rfc822-to-8bit (ORCPT ); Tue, 12 May 2020 22:45:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:54554 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726582AbgEMCpz (ORCPT ); Tue, 12 May 2020 22:45:55 -0400 From: bugzilla-daemon@bugzilla.kernel.org To: linux-xfs@vger.kernel.org Subject: [Bug 207711] New: xfs: data race on ctx->space_used in xlog_cil_insert_items() Date: Wed, 13 May 2020 02:45:54 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: AssignedTo filesystem_xfs@kernel-bugs.kernel.org X-Bugzilla-Product: File System X-Bugzilla-Component: XFS X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: baijiaju1990@gmail.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: filesystem_xfs@kernel-bugs.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version cf_kernel_version rep_platform op_sys cf_tree bug_status bug_severity priority component assigned_to reporter cf_regression Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=207711 Bug ID: 207711 Summary: xfs: data race on ctx->space_used in xlog_cil_insert_items() Product: File System Version: 2.5 Kernel Version: 5.4 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: XFS Assignee: filesystem_xfs@kernel-bugs.kernel.org Reporter: baijiaju1990@gmail.com Regression: No The functions xlog_cil_insert_items() and xlog_cil_push_background() are concurrently executed at runtime at the following call contexts: Thread 1: xfs_file_write_iter() xfs_file_buffered_aio_write() xfs_file_aio_write_checks() xfs_vn_update_time() xfs_trans_commit() __xfs_trans_commit() xfs_log_commit_cil() xlog_cil_insert_items() Thread 2: xfs_file_write_iter() xfs_file_buffered_aio_write() xfs_file_aio_write_checks() xfs_vn_update_time() xfs_trans_commit() __xfs_trans_commit() xfs_log_commit_cil() xlog_cil_push_background() In xlog_cil_insert_items(): ctx->space_used += len; In xlog_cil_push_background(): if (cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log)) The variables ctx->space_used and cil->xc_ctx->space_used access the same memory, and thus a data race can occur. This data race was found and actually reproduced by our concurrency fuzzer. I am not sure whether this data race is harmful and how to fix this data race properly, so I want to listen to your opinions, thanks :) -- You are receiving this mail because: You are watching the assignee of the bug.