INFO: task syz-executor.5:26377 blocked for more than 140 seconds. Not tainted 4.14.213-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28736 26377 20967 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:1724 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_vcpu_release+0x77/0xa0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2482 __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: 0033:0x417b71 RSP: 002b:00007ffdcf8fdec0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000417b71 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000257 R09: 0000000054bb625a R10: 00007ffdcf8fdfa0 R11: 0000000000000293 R12: ffffffffffffffff R13: 00000000001c5333 R14: 00000000000003e8 R15: 000000000119bf8c Showing all locks held in the system: 1 lock held by khungtaskd/1531: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1531 Comm: khungtaskd Not tainted 4.14.213-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8 Comm: rcu_preempt Not tainted 4.14.213-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880b5414200 task.stack: ffff8880b5418000 RIP: 0010:__hlist_del include/linux/list.h:676 [inline] RIP: 0010:detach_timer kernel/time/timer.c:792 [inline] RIP: 0010:detach_if_pending+0xb6/0x430 kernel/time/timer.c:809 RSP: 0018:ffff8880b541fbd8 EFLAGS: 00000083 RAX: ffff8880b5414200 RBX: ffff8880b541fd18 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000086 RBP: 0000000000000001 R08: ffffffff8b9a72d0 R09: 0000000000000001 R10: 0000000000000000 R11: ffff8880b5414200 R12: ffff8880ba522c48 R13: 0000000000000001 R14: ffff8880b541fd20 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8f8d60e000 CR3: 00000000b060e000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: try_to_del_timer_sync+0x9a/0xe0 kernel/time/timer.c:1181 del_timer_sync+0x17c/0x240 kernel/time/timer.c:1246 schedule_timeout+0x4b7/0xe90 kernel/time/timer.c:1748 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 00 e8 cf 04 0d 00 65 8b 2d 58 46 b7 7e 83 fd 07 0f 87 82 02 00 00 e8 ba 04 0d 00 89 ed 48 0f a3 2d 28 74 be 08 0f 82 1a 02 00 00 a5 04 0d 00 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea