INFO: task syz-executor.4:13263 can't die for more than 143 seconds. syz-executor.4 R running task 27688 13263 7704 0x00004006 Call Trace: Showing all locks held in the system: 3 locks held by kworker/u4:0/7: 1 lock held by khungtaskd/1161: #0: ffffffff899befc0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 1 lock held by in:imklog/6909: #0: ffff88809cb54b30 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 1 lock held by syz-executor.4/13263: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1161 Comm: khungtaskd Not tainted 5.7.0-rc1-next-20200415-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xde3/0x14e0 kernel/hung_task.c:333 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 13263 Comm: syz-executor.4 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__next_base kernel/time/hrtimer.c:491 [inline] RIP: 0010:__hrtimer_next_event_base+0x11c/0x260 kernel/time/hrtimer.c:511 Code: 48 89 d7 e8 36 a3 0f 00 4c 39 f3 7d 0f e8 ec a1 0f 00 48 83 3c 24 00 49 89 de 74 5d e8 dd a1 0f 00 31 ff 89 ee e8 74 a3 0f 00 <85> ed 74 2b e8 cb a1 0f 00 89 e9 b8 fe ff ff ff f3 48 0f bc c9 41 RSP: 0018:ffffc90000da8e98 EFLAGS: 00000046 RAX: 0000000080010002 RBX: 69f0c73bbab7ae6b RCX: ffffffff816392bc RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000004 R08: ffff8880945fe000 R09: ffffed1015ce710c R10: ffff8880ae73885b R11: ffffed1015ce710b R12: ffff8880ae729700 R13: ffff8880968e6c00 R14: 000000864aae1dc1 R15: dffffc0000000000 FS: 00007fcb94d25700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020c00000 CR3: 00000000636f1000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __hrtimer_get_next_event+0x117/0x210 kernel/time/hrtimer.c:585 hrtimer_interrupt+0x31f/0x770 kernel/time/hrtimer.c:1649 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline] smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:759 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x8c/0xe0 kernel/locking/spinlock.c:191 Code: 48 c7 c0 e0 c4 94 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 37 48 83 3d 1b 27 be 01 00 74 22 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 45 66 78 f9 65 8b 05 e6 80 2b 78 RSP: 0018:ffffc90015997aa0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff132989c RBX: 0000000000000286 RCX: 1ffffffff18714fa RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000286 RBP: ffff8880932d2f18 R08: 0000000000000001 R09: fffffbfff1862766 R10: ffffffff8c313b2f R11: fffffbfff1862765 R12: 0000000000000000 R13: 0000000000000286 R14: ffff8880932d2f18 R15: 0000000000000000 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] snd_seq_prioq_cell_out+0x1dc/0x340 sound/core/seq/seq_prioq.c:238 snd_seq_check_queue+0x1c4/0x450 sound/core/seq/seq_queue.c:261 snd_seq_enqueue_event+0x1f0/0x4c0 sound/core/seq/seq_queue.c:333 snd_seq_client_enqueue_event.constprop.0+0x23e/0x440 sound/core/seq/seq_clientmgr.c:974 snd_seq_write+0x386/0x690 sound/core/seq/seq_clientmgr.c:1093 __vfs_write+0x76/0x100 fs/read_write.c:495 vfs_write+0x268/0x5d0 fs/read_write.c:559 ksys_write+0x1ee/0x250 fs/read_write.c:612 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fcb94d24c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000050d060 RCX: 000000000045c829 RDX: 00000000fffffee4 RSI: 00000000200000c0 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000d12 R14: 00000000004cf441 R15: 00007fcb94d256d4