INFO: task syz-executor0:31809 blocked for more than 120 seconds. Not tainted 4.17.0-rc7+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D25320 31809 4536 0x20020004 Call Trace: context_switch kernel/sched/core.c:2859 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3501 schedule+0xef/0x430 kernel/sched/core.c:3545 blk_mq_freeze_queue_wait+0x1ce/0x460 block/blk-mq.c:152 blk_freeze_queue+0x4a/0x80 block/blk-mq.c:181 blk_mq_freeze_queue+0x15/0x20 block/blk-mq.c:190 loop_change_fd drivers/block/loop.c:689 [inline] lo_ioctl+0xa9a/0x2130 drivers/block/loop.c:1401 lo_compat_ioctl+0xc1/0x170 drivers/block/loop.c:1603 compat_blkdev_ioctl+0x3c2/0x1b20 block/compat_ioctl.c:406 __do_compat_sys_ioctl fs/compat_ioctl.c:1461 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:1407 [inline] __ia32_compat_sys_ioctl+0x221/0x640 fs/compat_ioctl.c:1407 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline] do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f80cb9 RSP: 002b:00000000f5f5b0ac EFLAGS: 00000282 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000000004c06 RDX: 0000000000000013 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/893: #0: 00000000cfedb980 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000cfedb980 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000d6cfcd19 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4373: #0: 000000002ea0f42a (&f->f_pos_lock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline] #0: 000000002ea0f42a (&f->f_pos_lock){+.+.}, at: double_lock_hb kernel/futex.c:1494 [inline] #0: 000000002ea0f42a (&f->f_pos_lock){+.+.}, at: futex_wake_op kernel/futex.c:1636 [inline] #0: 000000002ea0f42a (&f->f_pos_lock){+.+.}, at: do_futex+0x14da/0x27d0 kernel/futex.c:3537 2 locks held by getty/4463: #0: 00000000b39de73f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000df70c18e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4464: #0: 0000000088c7ecd4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c1a96f35 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4465: #0: 000000004daff348 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a6b1bb44 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4466: #0: 00000000252602b5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000001351bc14 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4467: #0: 0000000033f2fb9f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000bdb92a61 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4468: #0: 000000003845bcd3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000077e9b55b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4469: #0: 000000003034ae94 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ae0f4111 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 1 lock held by syz-executor0/31809: #0: 0000000023843869 (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8d/0x2130 drivers/block/loop.c:1392 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 893 Comm: khungtaskd Not tainted 4.17.0-rc7+ #105 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:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.17.0-rc7+ #105 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:scheduler_ipi+0x53e/0xa30 kernel/sched/core.c:1747 RSP: 0018:ffff8801daf07cf0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: 1ffff1003b5e0fa1 RCX: ffffed003b5e0fa1 RDX: dffffc0000000000 RSI: 1ffff1003b5e0fa5 RDI: ffffed003b5e0fa9 RBP: ffff8801daf07e90 R08: ffff8801daf2c788 R09: ffffed003b5e58f1 R10: ffffed003b5e58f1 R11: ffff8801daf2c78b R12: 000000000002c700 R13: 0000000000000000 R14: ffff8801daf07e68 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002119000 CR3: 00000001b1489000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_reschedule_interrupt+0xed/0x660 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:887 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801d9ae7c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b35cf8a RCX: 0000000000000000 RDX: 1ffffffff11a31b0 RSI: 0000000000000001 RDI: ffffffff88d18d80 RBP: ffff8801d9ae7c38 R08: ffffed003b5e46d3 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801d9ae7cf0 R14: ffffffff897bfc60 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0xc2/0x440 arch/x86/kernel/process.c:500 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:491 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x395/0x560 kernel/sched/idle.c:262 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:368 start_secondary+0x42b/0x5c0 arch/x86/kernel/smpboot.c:272 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242 Code: 88 00 00 00 e8 94 8a 62 00 f0 41 83 a4 24 88 00 00 00 fc e8 45 49 f4 ff 48 b9 00 00 00 00 00 fc ff df 31 c0 48 01 d9 48 8d 79 08 <48> c7 01 00 00 00 00 48 83 e7 f8 48 c7 41 24 00 00 00 00 48 29