kworker/dying (21) used greatest stack depth: 12864 bytes left INFO: task syz-executor1:31246 blocked for more than 120 seconds. Not tainted 4.14.0-rc5+ #136 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D17648 31246 23084 0x00000004 Call Trace: context_switch kernel/sched/core.c:2790 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3366 schedule+0xf5/0x430 kernel/sched/core.c:3425 io_schedule+0x1c/0x70 kernel/sched/core.c:5032 __blkdev_direct_IO_simple+0x74f/0xee0 fs/block_dev.c:253 blkdev_direct_IO+0xc8a/0x1000 fs/block_dev.c:440 generic_file_read_iter+0x4cc/0x28f0 mm/filemap.c:2230 blkdev_read_iter+0x105/0x170 fs/block_dev.c:1925 call_read_iter include/linux/fs.h:1764 [inline] generic_file_splice_read+0x3f9/0x7b0 fs/splice.c:307 do_splice_to+0x10a/0x160 fs/splice.c:880 splice_direct_to_actor+0x242/0x820 fs/splice.c:952 do_splice_direct+0x29b/0x3c0 fs/splice.c:1061 do_sendfile+0x5c9/0xe80 fs/read_write.c:1433 SYSC_sendfile64 fs/read_write.c:1488 [inline] SyS_sendfile64+0xbd/0x160 fs/read_write.c:1480 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x452779 RSP: 002b:00007f097a03cbe8 EFLAGS: 00000212 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452779 RDX: 0000000020a65000 RSI: 000000000000001a RDI: 000000000000001a RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000100000001 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a6f7ff R14: 00007f097a03d9c0 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:4544 1 lock held by rsyslogd/2865: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x12b/0x190 fs/file.c:767 2 locks held by getty/2948: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 2 locks held by getty/2949: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 2 locks held by getty/2950: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 2 locks held by getty/2951: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 2 locks held by getty/2952: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 2 locks held by getty/2953: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 2 locks held by getty/2954: #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+0x2ef/0x1a00 drivers/tty/n_tty.c:2133 1 lock held by syz-executor1/31250: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1350 1 lock held by syz-executor1/31263: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1350 1 lock held by syz-executor1/31265: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1350 1 lock held by syz-executor1/31269: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1350 1 lock held by blkid/31260: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1350 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 644 Comm: khungtaskd Not tainted 4.14.0-rc5+ #136 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:137 [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+0x35e/0x430 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 skipped: idling at pc 0xffffffff84d3ae76