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=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 7862DC43460 for ; Mon, 5 Apr 2021 03:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4451F61394 for ; Mon, 5 Apr 2021 03:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231887AbhDEDFD (ORCPT ); Sun, 4 Apr 2021 23:05:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230089AbhDEDFC (ORCPT ); Sun, 4 Apr 2021 23:05:02 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90DBFC061756; Sun, 4 Apr 2021 20:04:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=T4cf4ITid5Uw9btKpflcNe21wEChiEeglpEstacOk/Q=; b=gUuAnbQYjseOLeoHIILPujk6rJ QO/lsrfrY3OUtvpd5UK6mPpVRjKaRdiOlhy30zjz9jsU7QovUwQuRfGkEc2t7VRiiMkkxAjvIjL9D 5yihykTM/M4LILUTMmNqbsw9VckhH1Kq82Pt41YV2WOmtvNSirSVUY163Ox+aF26Pvdb/rgsPo28X gAj6FnqPtL1U+L96xcHqa+hByfETERlTRJLa+gsRQPU63v0I+8naz+Vjxknieul40acPH0IgW3YqS Hxd/K3BzEHRCc8ygq9y25vJdOhWE1k3ZQr8s8+YuiI91w9OulBFdt9U4RWiutF4WwcmE8tWzQkDrI wqhWPv4g==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lTFXi-00ArC6-E0; Mon, 05 Apr 2021 03:04:50 +0000 Date: Mon, 5 Apr 2021 04:04:46 +0100 From: Matthew Wilcox To: syzbot Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: [syzbot] WARNING: suspicious RCU usage in dput Message-ID: <20210405030446.GF2531743@casper.infradead.org> References: <0000000000007a4aad05bf088d43@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000000000007a4aad05bf088d43@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org #syz dup: WARNING: suspicious RCU usage in getname_flags On Fri, Apr 02, 2021 at 07:52:17PM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 1e43c377 Merge tag 'xtensa-20210329' of git://github.com/j.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=16d76301d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=78ef1d159159890 > dashboard link: https://syzkaller.appspot.com/bug?extid=bdef67a6b28a89e6fe71 > > 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+bdef67a6b28a89e6fe71@syzkaller.appspotmail.com > > ============================= > WARNING: suspicious RCU usage > 5.12.0-rc5-syzkaller #0 Not tainted > ----------------------------- > kernel/sched/core.c:8294 Illegal context switch in RCU-bh read-side critical section! > > other info that might help us debug this: > > > rcu_scheduler_active = 2, debug_locks = 0 > no locks held by systemd-udevd/4825. > > stack backtrace: > CPU: 1 PID: 4825 Comm: systemd-udevd Not tainted 5.12.0-rc5-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x141/0x1d7 lib/dump_stack.c:120 > ___might_sleep+0x229/0x2c0 kernel/sched/core.c:8294 > dput+0x4d/0xbc0 fs/dcache.c:870 > step_into+0x2cf/0x1c80 fs/namei.c:1778 > walk_component+0x171/0x6a0 fs/namei.c:1945 > link_path_walk.part.0+0x712/0xc90 fs/namei.c:2266 > link_path_walk fs/namei.c:2190 [inline] > path_lookupat+0xb7/0x830 fs/namei.c:2419 > filename_lookup+0x19f/0x560 fs/namei.c:2453 > do_readlinkat+0xcd/0x2f0 fs/stat.c:417 > __do_sys_readlinkat fs/stat.c:444 [inline] > __se_sys_readlinkat fs/stat.c:441 [inline] > __x64_sys_readlinkat+0x93/0xf0 fs/stat.c:441 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7fb5a7e200ba > Code: 48 8b 0d e1 bd 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 0b 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ae bd 2b 00 f7 d8 64 89 01 48 > RSP: 002b:00007ffc9c440e38 EFLAGS: 00000202 ORIG_RAX: 000000000000010b > RAX: ffffffffffffffda RBX: 00005604089e4380 RCX: 00007fb5a7e200ba > RDX: 00005604089e4380 RSI: 00007ffc9c440ec0 RDI: 00000000ffffff9c > RBP: 0000000000000064 R08: 00007fb5a80dcbc8 R09: 0000000000000070 > R10: 0000000000000063 R11: 0000000000000202 R12: 00007ffc9c440ec0 > R13: 00000000ffffff9c R14: 00007ffc9c440e90 R15: 0000000000000063 > > > --- > 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.