INFO: task syz-executor2:12570 blocked for more than 120 seconds. Not tainted 4.15.0-rc2-next-20171206+ #60 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D25016 12570 3352 0x00000004 Call Trace: context_switch kernel/sched/core.c:2800 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3376 schedule+0xf5/0x430 kernel/sched/core.c:3435 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601 block_ioctl+0xea/0x130 fs/block_dev.c:1860 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x4529d9 RSP: 002b:00007fad91aefc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 00000000004529d9 RDX: 0000000000000018 RSI: 0000000000004c00 RDI: 0000000000000017 RBP: 000000000000005b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ed928 R13: 00000000ffffffff R14: 00007fad91af06d4 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/673: #0: (rcu_read_lock){....}, at: [<00000000f15b74fb>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000f15b74fb>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000024f1ca37>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554 1 lock held by rsyslogd/2979: #0: (&f->f_pos_lock){+.+.}, at: [<00000000a0d5e790>] __fdget_pos+0x131/0x1a0 fs/file.c:765 2 locks held by getty/3061: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3062: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3063: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3064: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3065: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3066: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3067: #0: (&tty->ldisc_sem){++++}, at: [<000000009a956918>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000000d9336a1>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 1 lock held by syz-executor2/12570: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor7/12597: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor6/12583: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor6/12602: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor1/12590: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor1/12612: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor4/12594: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor4/12615: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 1 lock held by syz-executor0/12599: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000e507d893>] lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 673 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171206+ #60 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+0x37a/0x440 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517 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-rc2-next-20171206+ #60 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:reacquire_held_locks+0x2a2/0x3e0 kernel/locking/lockdep.c:3653 RSP: 0018:ffff8801db507aa0 EFLAGS: 00000046 RAX: 0000000000000030 RBX: 1ffff1003b6a0f5a RCX: ffff8801da388bb8 RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8801da388300 RBP: ffff8801db507c18 R08: 1ffffffff0d2baf7 R09: 000000000000000e R10: ffff8801da388300 R11: 0000000000000001 R12: ffff8801db507af0 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff87490d20 FS: 0000000000000000(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001ec2000 CR3: 00000001d0744000 CR4: 00000000001406e0 DR0: 0000000020001000 DR1: 0000000020001000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: seqcount_lockdep_reader_access include/linux/seqlock.h:82 [inline] read_seqcount_begin include/linux/seqlock.h:164 [inline] ktime_get+0x144/0x3a0 kernel/time/timekeeping.c:762 tick_nohz_irq_enter kernel/time/tick-sched.c:1102 [inline] tick_irq_enter+0x9e/0x390 kernel/time/tick-sched.c:1123 irq_enter+0xbd/0xe0 kernel/softirq.c:346 scheduler_ipi+0x246/0x830 kernel/sched/core.c:1794 smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:931 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801da397da8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b472fb8 RCX: 0000000000000000 RDX: 1ffffffff0bd9744 RSI: 0000000000000001 RDI: ffffffff85ecba20 RBP: ffff8801da397da8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801da397e60 R14: ffffffff865ef1a0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x430 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+0x18/0x20 kernel/sched/idle.c:351 start_secondary+0x2dd/0x3e0 arch/x86/kernel/smpboot.c:277 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: 04 b0 48 c1 e0 04 48 2d 50 01 00 00 48 05 20 cb fa 86 e9 26 ff ff ff 48 8d 65 d8 b8 01 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <31> c0 c3 89 75 98 44 89 45 ac 44 89 4d b0 48 89 55 b8 44 89 55