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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1C24C4708D for ; Wed, 4 Jan 2023 04:01:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CEAB88E0002; Tue, 3 Jan 2023 23:01:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C9AC78E0001; Tue, 3 Jan 2023 23:01:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B62148E0002; Tue, 3 Jan 2023 23:01:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id A2C618E0001 for ; Tue, 3 Jan 2023 23:01:51 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 69A33160680 for ; Wed, 4 Jan 2023 04:01:51 +0000 (UTC) X-FDA: 80315768022.25.5F33A90 Received: from r3-21.sinamail.sina.com.cn (r3-21.sinamail.sina.com.cn [202.108.3.21]) by imf09.hostedemail.com (Postfix) with ESMTP id 36183140009 for ; Wed, 4 Jan 2023 04:01:47 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf09.hostedemail.com: domain of hdanton@sina.com designates 202.108.3.21 as permitted sender) smtp.mailfrom=hdanton@sina.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1672804910; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WKlms7q3bxb0AzEAk2ln092qh/nowNCIW32bGwx+5fE=; b=QWAaIk4sRjHO7LY4vaozj37RLZ9D2nHjBHJMAT6DqrJnarsE5hpJJr+wUNosovXyNgrfxU Pg6ytA9TCHRI8bXdupJoTfj/hPTodYqaKfXX2Hrb9eYlRY0C0R/mt+ezk5BUwCrfQxLUl4 +oUZxtHYzWKivcEnb6ddt5aYkfmoHKQ= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf09.hostedemail.com: domain of hdanton@sina.com designates 202.108.3.21 as permitted sender) smtp.mailfrom=hdanton@sina.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1672804910; a=rsa-sha256; cv=none; b=PMn0zxP/ave1xUqDuGs90tJfFfBC7OxV7sZEDTN4pXnWksufcBXxRWFPFVo/h1Fj54S1je x5XbvAz1KKWTTnTLrtQRTvxP1Hj8idkeKdivzN56YqKbKbuJjPyndzHOP2nP+GrgwZgQlg 4ZLTcnLENnH/kADqChcnmSuIfoVmgIs= Received: from unknown (HELO localhost.localdomain)([114.249.57.238]) by sina.com (172.16.97.32) with ESMTP id 63B4F9530001B832; Wed, 4 Jan 2023 11:58:13 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 59355629903 From: Hillf Danton To: syzbot Cc: agruenba@redhat.com, linux-mm@kvack.org, Tetsuo Handa , Waiman Long , linux-kernel@vger.kernel.org, rpeterso@redhat.com, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] INFO: task hung in freeze_super (3) Date: Wed, 4 Jan 2023 12:01:32 +0800 Message-Id: <20230104040132.4103-1-hdanton@sina.com> In-Reply-To: <000000000000c921b105ef617f05@google.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 36183140009 X-Rspam-User: X-Stat-Signature: u7wk37qab1q8qsybbrhoox3skr61rucu X-HE-Tag: 1672804907-735473 X-HE-Meta: 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 Qn7nVNYD mycdPF/QSOC5fB2olXyr8NS4WxZm2GQsNQcJCg9Km9iSrpQuiI0heNF7qk7H3nGcocY4qRvyIAU7qzvI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 09 Dec 2022 01:08:38 -0800 > syzbot found the following issue on: > > HEAD commit: f3e8416619ce Merge tag 'soc-fixes-6.1-5' of git://git.kern.. > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=12fb534d880000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d58e7fe7f9cf5e24 > dashboard link: https://syzkaller.appspot.com/bug?extid=f51cb4b9afbd87ec06f2 > compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123d216b880000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e46f5b880000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/628abc27cbe7/disk-f3e84166.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/2f19ea836174/vmlinux-f3e84166.xz > kernel image: https://storage.googleapis.com/syzbot-assets/f2e1347e85a5/bzImage-f3e84166.xz > mounted in repro: https://storage.googleapis.com/syzbot-assets/c239a19c8749/mount_0.gz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+f51cb4b9afbd87ec06f2@syzkaller.appspotmail.com > > INFO: task kworker/0:1H:120 blocked for more than 143 seconds. > Not tainted 6.1.0-rc8-syzkaller-00035-gf3e8416619ce #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:kworker/0:1H state:D stack:23480 pid:120 ppid:2 flags:0x00004000 > Workqueue: glock_workqueue glock_work_func > Call Trace: > > context_switch kernel/sched/core.c:5209 [inline] > __schedule+0x8c9/0xd70 kernel/sched/core.c:6521 > schedule+0xcb/0x190 kernel/sched/core.c:6597 > rwsem_down_write_slowpath+0xfc1/0x1480 kernel/locking/rwsem.c:1190 > __down_write_common kernel/locking/rwsem.c:1305 [inline] > __down_write kernel/locking/rwsem.c:1314 [inline] > down_write+0x231/0x270 kernel/locking/rwsem.c:1563 > freeze_super+0x45/0x420 fs/super.c:1697 > freeze_go_sync+0x178/0x340 fs/gfs2/glops.c:573 > do_xmote+0x34d/0x13d0 fs/gfs2/glock.c:776 > glock_work_func+0x2c2/0x450 fs/gfs2/glock.c:1082 > process_one_work+0x877/0xdb0 kernel/workqueue.c:2289 > worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 > kthread+0x266/0x300 kernel/kthread.c:376 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 > > INFO: task syz-executor330:3631 blocked for more than 143 seconds. > Not tainted 6.1.0-rc8-syzkaller-00035-gf3e8416619ce #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:syz-executor330 state:D stack:20176 pid:3631 ppid:3630 flags:0x00004004 > Call Trace: > > context_switch kernel/sched/core.c:5209 [inline] > __schedule+0x8c9/0xd70 kernel/sched/core.c:6521 > schedule+0xcb/0x190 kernel/sched/core.c:6597 > schedule_timeout+0x98/0x2f0 kernel/time/timer.c:1911 > do_wait_for_common+0x3ea/0x560 kernel/sched/completion.c:85 > __wait_for_common kernel/sched/completion.c:106 [inline] > wait_for_common kernel/sched/completion.c:117 [inline] > wait_for_completion+0x46/0x60 kernel/sched/completion.c:138 > __flush_workqueue+0x74a/0x1680 kernel/workqueue.c:2861 > gfs2_gl_hash_clear+0xbe/0x300 fs/gfs2/glock.c:2262 > gfs2_fill_super+0x2202/0x2700 fs/gfs2/ops_fstype.c:1307 > get_tree_bdev+0x400/0x620 fs/super.c:1324 > gfs2_get_tree+0x50/0x210 fs/gfs2/ops_fstype.c:1330 > vfs_get_tree+0x88/0x270 fs/super.c:1531 > do_new_mount+0x289/0xad0 fs/namespace.c:3040 > do_mount fs/namespace.c:3383 [inline] > __do_sys_mount fs/namespace.c:3591 [inline] > __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f19da3f458a > RSP: 002b:00007ffd6b2d69e8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5 > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f19da3f458a > RDX: 0000000020000040 RSI: 000000002003b300 RDI: 00007ffd6b2d6a00 > RBP: 00007ffd6b2d6a00 R08: 00007ffd6b2d6a40 R09: 0000000000000002 > R10: 0000000000000000 R11: 0000000000000282 R12: 0000000000000004 > R13: 0000555556b0d2c0 R14: 0000000000000000 R15: 00007ffd6b2d6a40 > > > Showing all locks held in the system: > 1 lock held by rcu_tasks_kthre/12: > #0: ffffffff8d127330 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507 > 1 lock held by rcu_tasks_trace/13: > #0: ffffffff8d127b30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507 > 1 lock held by khungtaskd/28: > #0: ffffffff8d127160 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 > 3 locks held by kworker/0:1H/120: > #0: ffff8880194f5d38 ((wq_completion)glock_workqueue){+.+.}-{0:0}, at: process_one_work+0x7f2/0xdb0 > #1: ffffc90002587d00 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work+0x831/0xdb0 kernel/workqueue.c:2264 > #2: ffff888026c2c0e0 (&type->s_umount_key#42){+.+.}-{3:3}, at: freeze_super+0x45/0x420 fs/super.c:1697 > 2 locks held by getty/3308: > #0: ffff888028211098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 > #1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x53b/0x1650 drivers/tty/n_tty.c:2177 > 1 lock held by syz-executor330/3631: > #0: ffff888026c2c0e0 (&type->s_umount_key#41/1){+.+.}-{3:3}, at: alloc_super+0x212/0x920 fs/super.c:228 > syz-executor330/3631 kworker/0:1H/120 --- --- down_write_nested(&s->s_umount); glock_work_func() down_write(&sb->s_umount); flush_workqueue(glock_workqueue); No deadlock is reported yet. Whyyy? See if extending the aperture of wq->lockdep_map can catch it. #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master --- x/kernel/workqueue.c +++ y/kernel/workqueue.c @@ -2807,7 +2807,6 @@ void __flush_workqueue(struct workqueue_ return; lock_map_acquire(&wq->lockdep_map); - lock_map_release(&wq->lockdep_map); mutex_lock(&wq->mutex); @@ -2867,7 +2866,7 @@ void __flush_workqueue(struct workqueue_ * handling overflow. Non-first flushers can simply return. */ if (READ_ONCE(wq->first_flusher) != &this_flusher) - return; + goto out; mutex_lock(&wq->mutex); @@ -2942,6 +2941,8 @@ void __flush_workqueue(struct workqueue_ out_unlock: mutex_unlock(&wq->mutex); +out: + lock_map_release(&wq->lockdep_map); } EXPORT_SYMBOL(__flush_workqueue); --