INFO: task syz-executor1:25482 blocked for more than 120 seconds. Not tainted 4.14.0-rc2+ #103 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D20440 25482 18509 0x00000004 Call Trace: context_switch kernel/sched/core.c:2790 [inline] __schedule+0x8e8/0x2070 kernel/sched/core.c:3366 schedule+0xf5/0x430 kernel/sched/core.c:3425 schedule_timeout+0x1ce/0x250 kernel/time/timer.c:1720 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5020 do_wait_for_common kernel/sched/completion.c:90 [inline] __wait_for_common kernel/sched/completion.c:111 [inline] wait_for_common_io kernel/sched/completion.c:128 [inline] wait_for_completion_io+0x44b/0x7b0 kernel/sched/completion.c:176 submit_bio_wait+0x15e/0x200 block/bio.c:953 blkdev_issue_flush+0x1da/0x2d0 block/blk-flush.c:531 blkdev_fsync+0x86/0xb0 fs/block_dev.c:644 vfs_fsync_range+0x10a/0x250 fs/sync.c:195 vfs_fsync fs/sync.c:209 [inline] do_fsync+0x42/0x70 fs/sync.c:219 SYSC_fsync fs/sync.c:227 [inline] SyS_fsync+0x16/0x20 fs/sync.c:225 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x4520a9 RSP: 002b:00007f5b69139c08 EFLAGS: 00000216 ORIG_RAX: 000000000000004a RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004520a9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004ba2af R13: 00000000ffffffff R14: 00000000000000a6 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/644: #0: (rcu_read_lock){....}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4552 1 lock held by rsyslogd/2874: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x131/0x1a0 fs/file.c:767 2 locks held by getty/2957: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 2 locks held by getty/2958: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 2 locks held by getty/2959: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 2 locks held by getty/2960: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 2 locks held by getty/2961: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 2 locks held by getty/2962: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 2 locks held by getty/14541: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2133 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 644 Comm: khungtaskd Not tainted 4.14.0-rc2+ #103 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 nmi_cpu_backtrace+0x20e/0x240 lib/nmi_backtrace.c:102 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:61 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 trigger_all_cpu_backtrace include/linux/nmi.h:105 [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+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.14.0-rc2+ #103 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d9f8a300 task.stack: ffff8801d9f90000 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 RSP: 0018:ffff8801db307e20 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff8801db31db80 RCX: 0000000000000001 RDX: 1ffff1003b663b80 RSI: 000c51677c000000 RDI: 0000000000000001 RBP: ffff8801db307e48 R08: ffff88021fff905c R09: ffff88021fff9048 R10: ffff88021fff9050 R11: ffff88021fff905d R12: ffff8801db31dbe4 R13: ffff8801db31dc00 R14: 00000072cf04ef67 R15: ffffffff85ac99e0 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001b7a000 CR3: 00000001d2bc2000 CR4: 00000000001406e0 DR0: 0000000020001000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: irq_enter+0xbd/0xe0 kernel/softirq.c:345 scheduler_ipi+0x8c/0x460 kernel/sched/core.c:1784 smp_reschedule_interrupt+0xf2/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:794 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:53 RSP: 0018:ffff8801d9f97da8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b3f2fb8 RCX: 0000000000000000 RDX: 1ffffffff0b59340 RSI: 0000000000000001 RDI: ffffffff85ac9a00 RBP: ffff8801d9f97da8 R08: ffffffff857b4a68 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff85ac99f0 R13: ffff8801d9f97e60 R14: 0000000000000000 R15: ffffffff85ac99e0 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x460 arch/x86/kernel/process.c:341 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:332 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24e/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:351 start_secondary+0x2ea/0x3f0 arch/x86/kernel/smpboot.c:278 secondary_startup_64+0xa5/0xa5 arch/x86/kernel/head_64.S:235 Code: ff 4c 89 e7 e8 02 be 34 00 e9 32 fd ff ff 48 8b bd d0 fe ff ff e8 91 be 34 00 e9 c3 fc ff ff 90 90 90 90 90 90 90 90 90 90 90 90 <55> 65 48 8b 04 25 40 65 01 00 48 85 c0 48 89 e5 74 1a 65 8b 15