INFO: task syz-executor5:14689 blocked for more than 120 seconds. Not tainted 4.15.0-rc9+ #284 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D25520 14689 3738 0x00000004 Call Trace: context_switch kernel/sched/core.c:2799 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3375 schedule+0xf5/0x430 kernel/sched/core.c:3434 blk_mq_freeze_queue_wait+0x1bb/0x400 block/blk-mq.c:137 blk_freeze_queue+0x4a/0x80 block/blk-mq.c:166 blk_mq_freeze_queue+0x15/0x20 block/blk-mq.c:175 loop_set_status+0x1a2/0xf60 drivers/block/loop.c:1097 loop_set_status64+0x9d/0x110 drivers/block/loop.c:1271 lo_ioctl+0xd86/0x1b70 drivers/block/loop.c:1381 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601 block_ioctl+0xde/0x120 fs/block_dev.c:1860 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007f5d39f8ac58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000453299 RDX: 0000000020572000 RSI: 0000000000004c04 RDI: 0000000000000013 RBP: 000000000000061d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f8358 R13: 00000000ffffffff R14: 00007f5d39f8b6d4 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/760: #0: (rcu_read_lock){....}, at: [<000000009bad60f6>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000009bad60f6>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000091822ede>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4465 1 lock held by rsyslogd/3532: #0: (&f->f_pos_lock){+.+.}, at: [<0000000026dc7bbb>] __fdget_pos+0x12b/0x190 fs/file.c:770 2 locks held by getty/3655: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3656: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3657: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3658: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3659: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3660: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3661: #0: (&tty->ldisc_sem){++++}, at: [<00000000e174e707>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002b10cc15>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor5/14689: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000304bc073>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 760 Comm: khungtaskd Not tainted 4.15.0-rc9+ #284 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+0x194/0x257 lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc9+ #284 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:76 [inline] RIP: 0010:rcu_read_lock_sched_notrace include/linux/rcupdate.h:755 [inline] RIP: 0010:trace_softirq_raise include/trace/events/irq.h:156 [inline] RIP: 0010:__raise_softirq_irqoff kernel/softirq.c:443 [inline] RIP: 0010:raise_softirq_irqoff+0x220/0x320 kernel/softirq.c:417 RSP: 0018:ffff8801db307c90 EFLAGS: 00000083 RAX: 0000000000000001 RBX: 1ffff1003b660f93 RCX: dffffc0000000000 RDX: 1ffff1003b6659a2 RSI: 1ffff1003b660fc5 RDI: 0000000000000007 RBP: ffff8801db307d60 R08: 1ffff1003b665995 R09: ffff88021fff8048 R10: ffff88021fff8050 R11: ffff88021fff805d R12: 0000000000000007 R13: ffff8801db307d38 R14: ffff8801db307e68 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f21dfcb6140 CR3: 0000000006a22006 CR4: 00000000001606e0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: scheduler_ipi+0x50b/0x820 kernel/sched/core.c:1801 smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:961 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801d9f77cb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b3eef99 RCX: 0000000000000000 RDX: 1ffffffff0d59198 RSI: 0000000000000001 RDI: ffffffff86ac8cc0 RBP: ffff8801d9f77cb0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801d9f77d68 R14: ffffffff8725b4e0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x460 arch/x86/kernel/process.c:355 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:346 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24a/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351 start_secondary+0x40a/0x590 arch/x86/kernel/smpboot.c:268 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: 89 f2 48 c1 ea 03 80 3c 02 00 0f 85 d4 00 00 00 4d 8b 3e 4d 85 ff 75 b6 65 ff 0d 5c ff be 7e e9 62 fe ff ff 65 ff 05 50 ff be 7e <49> 8d 45 c0 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 48 01 d0