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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B58F8C00454 for ; Fri, 13 Dec 2019 22:04:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EDB5206C3 for ; Fri, 13 Dec 2019 22:04:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726752AbfLMWEK (ORCPT ); Fri, 13 Dec 2019 17:04:10 -0500 Received: from mail-io1-f69.google.com ([209.85.166.69]:40765 "EHLO mail-io1-f69.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbfLMWEK (ORCPT ); Fri, 13 Dec 2019 17:04:10 -0500 Received: by mail-io1-f69.google.com with SMTP id q19so786495ion.7 for ; Fri, 13 Dec 2019 14:04:08 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=74hTEiXuIBBuX+wNO/qGUSsAN9bF7EIfe65xbl5pH6Q=; b=FY9X3ExTD9QHwXOi3klFIiZ1gWTp0/jrBpLcXgW+o6aA+61X4YWSNa5OIy91BDUV0u GSptIhbxea/kFfj/XLtnYcr/rchxCaxjSjFDKe5r0zFis5etFuKeKCbEWz6ST6bU+zaG 4ho3/rOrLIkziuUcSNxH22A2ZLiUMBja8BrxcVqRfe5Mkl2ar86I1cCNWpPIwJvsoOJ2 Wtv0E2Bdu6M+mxqOdlImQcmuXAF6V7VEEBrmPWMhPYm5YUYpS/jMkWMlj+BvZkQ1jX5a zktZbKo/K+juR7DvDQLTRkUhD7VXTw5plAYgg2w+anfxWTABNyjxNMcemV+6gCSoxzTT pMbg== X-Gm-Message-State: APjAAAXtSiYYMeDYcVfDz3H7RoDzQTi/d0pJn9oCH5dxu423Xaum17hT AfMy87IHrVgD50/xSMLm1fViaSP+hywqPpY7Z59fHz1Qu3lq X-Google-Smtp-Source: APXvYqylWovhWQKc0/OSlbOTvzYKwq+BpoogqE6aMhNXYZrjpf4XHIQPpeaF7X4uEOpf6jmbE5EW4FR4gGvLFvoFx1v+vhzcuBr8 MIME-Version: 1.0 X-Received: by 2002:a6b:6310:: with SMTP id p16mr8895712iog.5.1576274648002; Fri, 13 Dec 2019 14:04:08 -0800 (PST) Date: Fri, 13 Dec 2019 14:04:07 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000076760205999d0a3b@google.com> Subject: KCSAN: data-race in link_path_walk.part.0 / page_get_link From: syzbot To: elver@google.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 5863cc79 x86, kcsan: Enable KCSAN for x86 git tree: https://github.com/google/ktsan.git kcsan console output: https://syzkaller.appspot.com/x/log.txt?x=143b67cee00000 kernel config: https://syzkaller.appspot.com/x/.config?x=186a3142a4cdd1db dashboard link: https://syzkaller.appspot.com/bug?extid=57b6149668c34058041c compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+57b6149668c34058041c@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in link_path_walk.part.0 / page_get_link read to 0xffff88809b36e056 of 1 bytes by task 8667 on cpu 0: link_path_walk.part.0+0x2d7/0xa90 fs/namei.c:2109 link_path_walk fs/namei.c:2259 [inline] path_lookupat.isra.0+0x77/0x5a0 fs/namei.c:2307 filename_lookup+0x145/0x2b0 fs/namei.c:2338 user_path_at_empty+0x4c/0x70 fs/namei.c:2598 user_path_at include/linux/namei.h:49 [inline] do_mount+0xc8/0x1560 fs/namespace.c:3081 ksys_mount+0xe8/0x160 fs/namespace.c:3352 __do_sys_mount fs/namespace.c:3366 [inline] __se_sys_mount fs/namespace.c:3363 [inline] __x64_sys_mount+0x70/0x90 fs/namespace.c:3363 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 write to 0xffff88809b36e056 of 1 bytes by task 8674 on cpu 1: nd_terminate_link include/linux/namei.h:75 [inline] page_get_link+0x115/0x280 fs/namei.c:4787 get_link fs/namei.c:1069 [inline] trailing_symlink+0x505/0x5a0 fs/namei.c:2253 path_openat+0x6cc/0x36e0 fs/namei.c:3527 do_filp_open+0x11e/0x1b0 fs/namei.c:3555 do_sys_open+0x3b3/0x4f0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x55/0x70 fs/open.c:1110 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 8674 Comm: syz-executor.5 Not tainted 5.4.0-rc7+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.