From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 36C1E25E47D for ; Sun, 31 Aug 2025 12:45:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756644306; cv=none; b=kfT6fvkYbiQ9c341ZSHyXnUwF1dbmBWr8se7xFwW5X58eY9IrhnFoy/nlXh9FXIvH/JKtNcYI4gNlnkHaKwQ6cSoNIfTez61DxEkhTbtnl3n1zzXJYqhALEwD1GPj0AaXYDju5jqhFvZ+CIkLWGyUGG223b1l4JjOMLI9K/bHYY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756644306; c=relaxed/simple; bh=Q+C3Q42XMMA4CO1tce+/iiIEHy7/uCLYowNcRNTa+fg=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=gQLp8pYLQdaOGnL5p7ft25bJ3L2+b1NqgL3xii2bjJtz5vp+0Qvb+kYAZUHR4HZRZ8DiG2w1XzS48duEIA9qvMx77EdEkXCT0ltS/zccyjQvuc85Wi5SOXO4zCVFM+AEK8pff3jTucSR6euYL0bWr4ivjOdyEZkwfLFQhLMDbQY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-il1-f200.google.com with SMTP id e9e14a558f8ab-3ed0ba44c87so42928535ab.0 for ; Sun, 31 Aug 2025 05:45:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756644303; x=1757249103; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+R4cnDIvQcPBSkv9Qkr1oJrv/pIHrwS+U5hGlqqSfLY=; b=WclxglSTzKp7hgFJzTgdIO3aCr/S1U7es2Vv5L9hmYhBskBECntoyz+kPyHsYuYc/o ioeUTeMWRsysyqB0Z7mMWjulyKYW3q7I/71+MF3SOxdPPuYn3bKEKZjcexXFVKnN3FZr Qx7zf1/vPFDx9X3fNyFAoch/017HvFe5QjXrgcBcLy0Rm7x9+WGoMu4rXJ/Kze1kngsy fo0vUj2l3F6WIWfp8ACcwdUxJrQibl6jNoHHbHoMXNpPTWbA6vleF60/UYaa/oikhCe6 oPXT5hZOg99Pbd/5tmZIzK9naVbglwLpZv90TChlLoy0ofCIXc8ILeoMXRvNP/5Sf9z3 2ecw== X-Gm-Message-State: AOJu0YyxcLO25mclo11F/1VoIjP8AtMpj/sjFNHQ+SWlmvj1SPpuUpy8 0s3jAHnAxELgXD7UhDuhxaZUucvDYuPyLggQAuJYhuB7tnizXgeouf8vvSrx9SeDLQddZNZBHta xtsuCZ/uDU1hASBNQi0z1O2nhp7uxYagDsI2SJZdiiTEnj9iSHmCjA2/+y+s= X-Google-Smtp-Source: AGHT+IGXFqzJ+4uuYAuOD4PlZ2H5T4O0LVBH1AxysYQX8WoSOUYd7YmV5QTYGt7hZEZWc8JHtCSGx+9NEcQ/36RlpEiQJev+wE3R Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:2165:b0:3e5:51bb:9cd9 with SMTP id e9e14a558f8ab-3f400674ac2mr111972285ab.8.1756644303371; Sun, 31 Aug 2025 05:45:03 -0700 (PDT) Date: Sun, 31 Aug 2025 05:45:03 -0700 In-Reply-To: <20250831080725-mutt-send-email-mst@kernel.org> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68b443cf.050a0220.3db4df.01b4.GAE@google.com> Subject: Re: [syzbot] [net] [virt] INFO: task hung in __vhost_worker_flush From: syzbot To: linux-kernel@vger.kernel.org, mst@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: INFO: task hung in __vhost_worker_flush INFO: task syz.0.17:6636 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:27880 pid:6636 tgid:6636 ppid:6529 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x2ff/0x4e0 kernel/sched/completion.c:116 __vhost_worker_flush+0x1cd/0x210 drivers/vhost/vhost.c:288 vhost_worker_flush drivers/vhost/vhost.c:295 [inline] vhost_dev_flush+0xac/0x110 drivers/vhost/vhost.c:305 vhost_vsock_flush drivers/vhost/vsock.c:697 [inline] vhost_vsock_dev_release+0x19f/0x400 drivers/vhost/vsock.c:749 __fput+0x402/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f978f78ebe9 RSP: 002b:00007ffc3ab7e268 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f978f9c7da0 RCX: 00007f978f78ebe9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f978f9c7da0 R08: 0000000000000000 R09: 000000083ab7e55f R10: 00007f978f9c7cb0 R11: 0000000000000246 R12: 000000000001d01b R13: 00007ffc3ab7e360 R14: ffffffffffffffff R15: 00007ffc3ab7e380 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e5c2a40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c2a40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c2a40 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770 5 locks held by kworker/u8:2/36: 2 locks held by udevd/5203: #0: ffff8880b843a2d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:606 #1: ffff8880b8424088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2c1/0x8e0 kernel/sched/psi.c:987 2 locks held by getty/5594: #0: ffff88814dcd80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:470 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5154 Comm: kworker/u9:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: hci9 hci_cmd_timeout RIP: 0010:unwind_get_return_address+0x4e/0xa0 arch/x86/kernel/unwind_orc.c:369 Code: 7e 59 8b 03 85 c0 75 09 31 c0 5b 5d e9 0b 32 1a 0a 48 b8 00 00 00 00 00 fc ff df 48 8d 6b 48 48 89 ea 48 c1 ea 03 80 3c 02 00 <75> 36 48 8b 7b 48 e8 57 9c 19 00 85 c0 74 cf 48 b8 00 00 00 00 00 RSP: 0018:ffffc90000a08828 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffc90000a08840 RCX: ffffc90000a08794 RDX: 1ffff92000141111 RSI: ffffffff8de01fb5 RDI: ffffc90000a08840 RBP: ffffc90000a08888 R08: ffffffff913e3972 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000007c23 R12: ffffffff81a6bcc0 R13: ffffc90000a08900 R14: 0000000000000000 R15: ffff88803756c880 FS: 0000000000000000(0000) GS:ffff888124841000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffeff55cff8 CR3: 0000000028574000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0xa6/0x100 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548 insert_work+0x36/0x230 kernel/workqueue.c:2183 __queue_work+0x97e/0x10f0 kernel/workqueue.c:2341 call_timer_fn+0x197/0x620 kernel/time/timer.c:1747 expire_timers kernel/time/timer.c:1793 [inline] __run_timers+0x569/0x960 kernel/time/timer.c:2372 __run_timer_base kernel/time/timer.c:2384 [inline] __run_timer_base kernel/time/timer.c:2376 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2393 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2061 [inline] RIP: 0010:vprintk_emit+0x567/0x6d0 kernel/printk/printk.c:2449 Code: 00 4d 85 ed 0f 85 19 01 00 00 e8 64 59 20 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 c2 54 20 00 48 85 ed 0f 85 25 01 00 00 44 59 20 00 45 31 c9 41 b8 01 00 00 00 31 c9 48 8d 05 00 00 00 RSP: 0018:ffffc900105c79c8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000023 RCX: ffffffff819ac02c RDX: ffff88803756c880 RSI: ffffffff819ac036 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 1ffff920020b8f3b R13: 0000000000000200 R14: ffff8880212b8000 R15: ffffc900105c7a90 _printk+0xc7/0x100 kernel/printk/printk.c:2475 bt_err+0xe4/0x120 net/bluetooth/lib.c:296 hci_cmd_timeout+0x1ff/0x260 net/bluetooth/hci_core.c:1475 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Tested on: commit: d9ea58b5 vdpa: Fix IDR memory leak in VDUSE module exit git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=11068662580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4931b9b3bcbb1c4c dashboard link: https://syzkaller.appspot.com/bug?extid=7f3bbe59e8dd2328a990 compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 Note: no patches were applied.