INFO: task syz-executor3:14683 blocked for more than 120 seconds. Not tainted 4.15.0-rc6-next-20180105+ #89 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D28648 14683 3684 0x00000004 Call Trace: context_switch kernel/sched/core.c:2800 [inline] __schedule+0x850/0x1e10 kernel/sched/core.c:3376 schedule+0x7c/0x1a0 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+0x7e4/0x1550 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x1003/0x1910 block/ioctl.c:601 block_ioctl+0xde/0x120 fs/block_dev.c:1859 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x190/0xfe0 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x23/0x9a RIP: 0033:0x452ac9 RSP: 002b:00007f60322ddc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000071bf58 RCX: 0000000000452ac9 RDX: 0000000000000016 RSI: 0000000000004c00 RDI: 0000000000000017 RBP: 00000000000003a3 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f37e8 R13: 00000000ffffffff R14: 00007f60322de6d4 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/739: #0: (rcu_read_lock){....}, at: [<0000000067dc4e08>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<0000000067dc4e08>] watchdog+0x122/0xab0 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000552689db>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4464 2 locks held by rsyslogd/3313: #0: (&f->f_pos_lock){+.+.}, at: [<00000000ccd22503>] __fdget_pos+0xa2/0xc0 fs/file.c:765 #1: (log_wait.lock){-...}, at: [<0000000098dc0f14>] fs_reclaim_acquire.part.83+0x0/0x30 mm/page_alloc.c:499 2 locks held by getty/3437: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 2 locks held by getty/3438: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 2 locks held by getty/3439: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 2 locks held by getty/3440: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 2 locks held by getty/3441: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 2 locks held by getty/3442: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 1 lock held by syz-executor3/14683: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000020bf2a68>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 1 lock held by syz-executor3/14691: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000020bf2a68>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 2 locks held by getty/14700: #0: (&tty->ldisc_sem){++++}, at: [<0000000070a76eed>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004e74cdab>] n_tty_read+0x1ec/0x1660 drivers/tty/n_tty.c:2131 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 739 Comm: khungtaskd Not tainted 4.15.0-rc6-next-20180105+ #89 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+0x137/0x198 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+0x73d/0xab0 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524 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-rc6-next-20180105+ #89 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__do_softirq+0x6d0/0x99f kernel/softirq.c:314 RSP: 0018:ffff8801db507f60 EFLAGS: 00000096 RAX: 0000000000000000 RBX: ffff8801da39e440 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801da36634c RBP: ffff8801db507f78 R08: 0000000000000001 R09: 0000000000000101 R10: 0000000000000000 R11: 0000000000000001 R12: ffff8801da366300 R13: 0000000000000007 R14: ffffffff85e09140 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa046345000 CR3: 0000000005e22006 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: invoke_softirq kernel/softirq.c:365 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 scheduler_ipi+0x2c5/0x450 kernel/sched/core.c:1804 smp_reschedule_interrupt+0x67/0x470 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:944 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801da377d70 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: ffff8801da366300 RCX: 0000000000000000 RDX: 1ffffffff0bd90a0 RSI: 0000000000000001 RDI: ffffffff85ec8500 RBP: ffff8801da377d70 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff86638fe0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0x52/0x310 arch/x86/kernel/process.c:354 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:345 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+0xbe/0xd0 kernel/sched/idle.c:351 start_secondary+0x3e2/0x550 arch/x86/kernel/smpboot.c:267 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 80 02 00 00 8b 45 8c 25 00 08 00 00 09 43 4c 48 83 c4 58 5b 41 5c <41> 5d 41 5e 41 5f 5d c3 48 89 d8 48 c1 e8 03 42 80 3c 38 00 0f