INFO: task syz-executor.0:32303 blocked for more than 140 seconds. Not tainted 4.14.290-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28912 32303 8000 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 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:555 kvm_mmu_pre_destroy_vm+0x41/0x50 arch/x86/kvm/mmu.c:5912 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:781 [inline] kvm_put_kvm+0x30a/0xab0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:819 kvm_vm_release+0x3f/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:830 __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: 0033:0x7fd200ccce4b RSP: 002b:00007ffd3fec9020 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00007fd200ccce4b RDX: 00007fd200e319e0 RSI: ffffffffffffffff RDI: 0000000000000004 RBP: 00007fd200e2e960 R08: 0000000000000000 R09: 00007fd200e319e8 R10: 00007ffd3fec9120 R11: 0000000000000293 R12: 00000000001fdd6e R13: 00007ffd3fec9120 R14: 00007fd200e2cf60 R15: 0000000000000032 Showing all locks held in the system: 1 lock held by khungtaskd/1534: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1534 Comm: khungtaskd Not tainted 4.14.290-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 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: 11572 Comm: syz-executor.2 Not tainted 4.14.290-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 task: ffff888087df2680 task.stack: ffff88809bb70000 RIP: 0010:__hlist_del include/linux/list.h:686 [inline] RIP: 0010:hlist_del include/linux/list.h:695 [inline] RIP: 0010:alloc_object lib/debugobjects.c:158 [inline] RIP: 0010:__debug_object_init+0x209/0x7a0 lib/debugobjects.c:349 RSP: 0018:ffff88809bb779e8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 1ffff1101376ef43 RCX: 000000000000717c RDX: 1ffff110140517ce RSI: 0000000000000001 RDI: ffff8880a028be84 RBP: ffff88809bb77ad0 R08: ffffffff8b9d96e0 R09: 00000000000c0002 R10: ffff8880a028be80 R11: ffff888087df2680 R12: 0000000000000086 R13: ffff8880a028be70 R14: ffffffff8c007188 R15: 0000000000054280 FS: 00007f59667ec700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5967f8b090 CR3: 00000000a57d8000 CR4: 00000000003426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __init_work kernel/workqueue.c:505 [inline] insert_wq_barrier kernel/workqueue.c:2501 [inline] start_flush_work kernel/workqueue.c:2849 [inline] flush_work+0x1ee/0x770 kernel/workqueue.c:2893 snd_seq_client_use_ptr+0x2dc/0x370 sound/core/seq/seq_clientmgr.c:164 snd_seq_ioctl_running_mode+0x3b/0x140 sound/core/seq/seq_clientmgr.c:1175 snd_seq_ioctl+0x1af/0x310 sound/core/seq/seq_clientmgr.c:2144 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f5967e77209 RSP: 002b:00007f59667ec168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5967f89f60 RCX: 00007f5967e77209 RDX: 0000000020000040 RSI: 00000000c0105303 RDI: 0000000000000003 RBP: 00007f5967ed1161 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc2976dc5f R14: 00007f59667ec300 R15: 0000000000022000 Code: 84 d2 0f 85 c8 04 00 00 4c 89 ea 41 c7 45 14 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 8e 04 00 00 <49> 8d 7d 08 49 8b 45 00 48 ba 00 00 00 00 00 fc ff df 48 89 f9