INFO: task syz-executor148:4500 blocked for more than 120 seconds. Not tainted 4.17.0-rc2+ #23 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor148 D16648 4500 4481 0x00000000 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 blk_mq_freeze_queue_wait+0x1ce/0x460 block/blk-mq.c:136 blk_freeze_queue+0x4a/0x80 block/blk-mq.c:165 blk_mq_freeze_queue+0x15/0x20 block/blk-mq.c:174 loop_clr_fd+0x226/0xb80 drivers/block/loop.c:1047 lo_ioctl+0x642/0x2130 drivers/block/loop.c:1404 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x9b6/0x2020 block/ioctl.c:601 block_ioctl+0xee/0x130 fs/block_dev.c:1877 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x449789 RSP: 002b:00007f210fae5da8 EFLAGS: 00000297 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006dac3c RCX: 0000000000449789 RDX: 0000000000449789 RSI: 0000000000004c01 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000297 R12: 00000000006dac38 R13: 0030656c69662f2e R14: 6f6f6c2f7665642f R15: 0000000000000007 Showing all locks held in the system: 2 locks held by khungtaskd/893: #0: 0000000045f40930 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 0000000045f40930 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 0000000081898718 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4362: #0: 000000002e322c73 (&f->f_pos_lock){+.+.}, at: __run_timers+0x16e/0xc50 kernel/time/timer.c:1658 2 locks held by getty/4452: #0: 000000003abe4bd2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000035e35fb8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4453: #0: 000000004e78faf9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000044d079f2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4454: #0: 0000000037bf7fca (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000fc65c2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4455: #0: 00000000650b41ff (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000f8a69a89 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4456: #0: 0000000033547e18 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000c85318d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4457: #0: 00000000e5cb3908 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000009fc1aed4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4458: #0: 0000000055360c24 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000002bcd4fa8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 1 lock held by syz-executor148/4486: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/4500: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/4514: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/4515: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/4517: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/5006: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/5008: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/5009: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/5011: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/5012: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/5014: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 1 lock held by syz-executor148/4483: #0: 0000000004c28cff (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1799 [inline] #0: 0000000004c28cff (&rq->lock){-.-.}, at: __schedule+0x246/0x1e30 kernel/sched/core.c:3428 1 lock held by blkid/5016: #0: 00000000bf14345a (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1391 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 893 Comm: khungtaskd Not tainted 4.17.0-rc2+ #23 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+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4495 Comm: syz-executor148 Not tainted 4.17.0-rc2+ #23 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_lockdep_rcu_enabled.part.1+0x3b/0x60 kernel/rcu/update.c:301 RSP: 0018:ffff8801d3ccefe0 EFLAGS: 00000046 RAX: 0000000000000007 RBX: ffff8801b142c200 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff8801b142ca34 RBP: ffff8801d3ccefe8 R08: ffffed003b5c46c3 R09: ffffed003b5c46c2 R10: ffffed003b5c46c2 R11: ffff8801dae23613 R12: 1ffff1003a799e26 R13: ffff8801d3ccf170 R14: 0000000000000000 R15: ffff8801b142c200 FS: 00007f210fb07700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f16b38df9ce CR3: 00000001b19db000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_lockdep_rcu_enabled+0x77/0x90 kernel/rcu/update.c:300 trace_rcu_utilization include/trace/events/rcu.h:21 [inline] rcu_note_context_switch+0x554/0x710 kernel/rcu/tree.c:456 __schedule+0x23e/0x1e30 kernel/sched/core.c:3418 schedule+0xef/0x430 kernel/sched/core.c:3549 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x3e8/0x820 kernel/futex.c:2530 futex_wait+0x450/0x9f0 kernel/futex.c:2645 do_futex+0x336/0x27d0 kernel/futex.c:3527 __do_sys_futex kernel/futex.c:3587 [inline] __se_sys_futex kernel/futex.c:3555 [inline] __x64_sys_futex+0x46a/0x680 kernel/futex.c:3555 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x449789 RSP: 002b:00007f210fb06da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000449789 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dac24 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac20 R13: 0030656c69662f2e R14: 6f6f6c2f7665642f R15: 0000000000000007 Code: 48 8b 1c 25 c0 ed 01 00 48 8d bb 34 08 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 10 <8b> 93 34 08 00 00 31 c0 5b 5d 85 d2 0f 94 c0 c3 e8 70 ed 51 00