INFO: task hung in kvm_mmu_pre_destroy_vm (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2b791501 Linux 4.14.203
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=169767a8500000
kernel config: https://syzkaller.appspot.com/x/.config?x=e52bb6f2a595a463
dashboard link: https://syzkaller.appspot.com/bug?extid=8301e5c2288882c02c20
compiler: gcc (GCC) 10.1.0-syz 20200507

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+8301e5...@syzkaller.appspotmail.com

INFO: task syz-executor.2:11778 blocked for more than 140 seconds.
Not tainted 4.14.203-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D28912 11778 9992 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x88b/0x1de0 kernel/sched/core.c:3384
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1731
do_wait_for_common kernel/sched/completion.c:91 [inline]
__wait_for_common kernel/sched/completion.c:112 [inline]
wait_for_common+0x272/0x430 kernel/sched/completion.c:123
kthread_stop+0xce/0x640 kernel/kthread.c:530
kvm_mmu_pre_destroy_vm+0x41/0x4f arch/x86/kvm/mmu.c:5903
kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:770 [inline]
kvm_put_kvm+0x30a/0xa90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:807
kvm_vm_release+0x3f/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:818
__fput+0x25f/0x7a0 fs/file_table.c:210
task_work_run+0x11f/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x417811
RSP: 002b:00007ffd3205f080 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000417811
RDX: 0000000000000000 RSI: 0000000000000256 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000054bb6256 R09: 0000000054bb625a
R10: 00007ffd3205f160 R11: 0000000000000293 R12: 000000000118c9a0
R13: 000000000118c9a0 R14: 00000000000003e8 R15: 000000000118bf2c

Showing all locks held in the system:
1 lock held by khungtaskd/1523:
#0: (tasklist_lock){.+.+}, at: [<ffffffff81430c94>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
2 locks held by agetty/7691:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff835e2522>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff835d7873>] n_tty_read+0x1e3/0x1680 drivers/tty/n_tty.c:2156

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1523 Comm: khungtaskd Not tainted 4.14.203-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5b9/0xb40 kernel/hung_task.c:274
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9789 Comm: kworker/u4:10 Not tainted 4.14.203-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
task: ffff88809291c200 task.stack: ffff888061248000
RIP: 0010:__lock_acquire+0x225/0x3f20 kernel/locking/lockdep.c:3396
RSP: 0018:ffff8880ba407c98 EFLAGS: 00000006
RAX: ffffffff8b9d55d0 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 1ffffffff11f077a RSI: 0000000000000000 RDI: ffffffff88f83bd0
RBP: 0000000000000002 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: ffff88809291c200 R12: ffffffff88f83bc8
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8beb4d40
FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c01067d000 CR3: 0000000097d94000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
seqcount_lockdep_reader_access include/linux/seqlock.h:81 [inline]
read_seqcount_begin include/linux/seqlock.h:164 [inline]
ktime_get_update_offsets_now+0xc1/0x3f0 kernel/time/timekeeping.c:2229
hrtimer_update_base kernel/time/hrtimer.c:505 [inline]
hrtimer_interrupt+0x364/0x5e0 kernel/time/hrtimer.c:1353
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1100
apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
</IRQ>
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:774 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:796 [inline]
RIP: 0010:lock_acquire+0x97/0x3f0 kernel/locking/lockdep.c:3993
RSP: 0018:ffff88806124fc78 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff11e1230 RBX: ffff88809291c200 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff88809291ca84
RBP: ffffffff88f77500 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88809291c200 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000
Code: 4b 8d 7c f4 08 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 5e 2a 00 00 4b 8b 44 f4 08 48 85 c0 0f 84 31 ff ff ff f0 ff 80 38 01 00 00 <49> 8d b3 80 08 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 f1 48


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.