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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EFA0C433EF for ; Mon, 25 Oct 2021 10:32:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1CA0C60EE9 for ; Mon, 25 Oct 2021 10:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232874AbhJYKec (ORCPT ); Mon, 25 Oct 2021 06:34:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230013AbhJYKe1 (ORCPT ); Mon, 25 Oct 2021 06:34:27 -0400 Received: from mail-oi1-x231.google.com (mail-oi1-x231.google.com [IPv6:2607:f8b0:4864:20::231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B774DC061348 for ; Mon, 25 Oct 2021 03:32:05 -0700 (PDT) Received: by mail-oi1-x231.google.com with SMTP id u69so14894105oie.3 for ; Mon, 25 Oct 2021 03:32:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=D0QnWPztlsrRoM5HO4MFrl5hX+n1/I11tCMVuj+w7U8=; b=gh2C0oDeLRx4W05Z5QcTixxzocX+J2wuaAYBOBR58Ea1BiaAkWbGE2t7RZknfSK8FF F2bMhbyhrTceCH4kWyuqHoL5gYddSREl0Ljw5a00FKyot0RHun7Xd7NSEcA4hwQ56bnr zhoDY+a6CNDE/hQaJuw3XmC3pBRFZSB7RGOhI+/gH3qVk0Su95s7dnT9Pqwva+xG1lxH deBbkAR58GQYNrWUr2W7xJi7mPt9B5oUy5lrWYQ0v0ORb29s4FD9F61NWiYdoq1rnRFg 93dkxJuzfe1V9eSAxPEF8OWRVvfJRLkYVwo6xo9N3ti5oqIWC3VXx5V437QWSDRgd7J3 SUXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=D0QnWPztlsrRoM5HO4MFrl5hX+n1/I11tCMVuj+w7U8=; b=MXNnRDh9/rvttYfvOAroyYU168aDsrZYrEvdYjiq8q//gfnkJpCzfX2770wza0iNyy FrgZ29YrSp2pghSLde3GkZZVPSbPuF07BknQb5nCEbtF+Pg+u7GFLnWwUxDcMdhzlZPq RF0hCFS3WiHh2bbJc2U41qRT2BfYzeecmNDlcmtp2bAPPcJcsK249MjEu4MuQ3qfI1nt ecUHAPuqzqhjnTE01iTY8mAXPMTmDdV27GSOH5jzFkYxoWHElzIsM6oaiqHHz5m0UPKg RO3srrRYo+Sw+xknL9pUR4rssqOAtZ1z+j0xkdXf9E/r70O1M97R98ktVWVkFr/6H/RG vD5A== X-Gm-Message-State: AOAM5331XwWAHGuehbCBxzcXZ0T49rLXYQQeQY+EN27PAqNT/YxTE3Nj In+WOVSTTACNYL/wkgObvpgRixrhwwK1pDahi7WV/w== X-Google-Smtp-Source: ABdhPJz1wKIV7+08Iah66Oe22tvpOMW6pVLQVVTYmBXVxB5VceXtYx/xZf8ft4WIDG+m7H8oa7ejZPfQXKcJWUDINis= X-Received: by 2002:a05:6808:6ce:: with SMTP id m14mr11466075oih.134.1635157924929; Mon, 25 Oct 2021 03:32:04 -0700 (PDT) MIME-Version: 1.0 References: <000000000000ddb95c05cf2ad54a@google.com> In-Reply-To: <000000000000ddb95c05cf2ad54a@google.com> From: Marco Elver Date: Mon, 25 Oct 2021 12:31:53 +0200 Message-ID: Subject: Re: [syzbot] KCSAN: data-race in call_rcu / rcu_gp_fqs_loop To: syzbot , "Paul E. McKenney" , rcu@vger.kernel.org Cc: 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" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +Cc Paul data race is in rcu code, presumably not yet discovered by rcutorture? On Mon, 25 Oct 2021 at 12:29, syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 9c0c4d24ac00 Merge tag 'block-5.15-2021-10-22' of git://gi.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=159c4954b00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=6339b6ea86d89fd7 > dashboard link: https://syzkaller.appspot.com/bug?extid=4dfb96a94317a78f44d9 > compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+4dfb96a94317a78f44d9@syzkaller.appspotmail.com > > ================================================================== > BUG: KCSAN: data-race in call_rcu / rcu_gp_fqs_loop > > write to 0xffffffff837342e0 of 8 bytes by task 11 on cpu 1: > rcu_gp_fqs kernel/rcu/tree.c:1910 [inline] > rcu_gp_fqs_loop+0x348/0x470 kernel/rcu/tree.c:1971 > rcu_gp_kthread+0x25/0x1a0 kernel/rcu/tree.c:2130 > kthread+0x262/0x280 kernel/kthread.c:319 > ret_from_fork+0x1f/0x30 > > read to 0xffffffff837342e0 of 8 bytes by task 379 on cpu 0: > __call_rcu_core kernel/rcu/tree.c:2904 [inline] > __call_rcu kernel/rcu/tree.c:3020 [inline] > call_rcu+0x4c0/0x6d0 kernel/rcu/tree.c:3067 > __dentry_kill+0x3ec/0x4e0 fs/dcache.c:596 > dput+0xc6/0x360 fs/dcache.c:888 > do_unlinkat+0x2a8/0x540 fs/namei.c:4172 > __do_sys_unlink fs/namei.c:4217 [inline] > __se_sys_unlink fs/namei.c:4215 [inline] > __x64_sys_unlink+0x2c/0x30 fs/namei.c:4215 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > value changed: 0x0000000000005c0d -> 0x0000000000005c0e > > Reported by Kernel Concurrency Sanitizer on: > CPU: 0 PID: 379 Comm: udevd Tainted: G W 5.15.0-rc6-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > ================================================================== > > > --- > This report 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 issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.