INFO: task syz-executor.0:4382 blocked for more than 143 seconds. Not tainted 5.1.0-rc4-next-20190415 #25 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D30336 4382 7846 0x00000004 Call Trace: context_switch kernel/sched/core.c:2876 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3517 schedule+0x92/0x180 kernel/sched/core.c:3561 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1783 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __io_uring_register+0xb6/0x1fd0 fs/io_uring.c:2930 __do_sys_io_uring_register fs/io_uring.c:2980 [inline] __se_sys_io_uring_register fs/io_uring.c:2962 [inline] __x64_sys_io_uring_register+0x193/0x1f0 fs/io_uring.c:2962 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 0f 86 df 00 00 00 48 83 ec 30 48 89 6c 24 28 48 8d 6c 24 28 48 8b 42 08 48 8b 48 70 <48> 89 4c 24 20 48 8b 10 48 89 54 24 18 48 8b 40 08 48 89 44 24 10 RSP: 002b:00007f94bcb40c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458c29 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000003 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f94bcb416d4 R13: 00000000004cb6f0 R14: 00000000004d2168 R15: 00000000ffffffff INFO: task syz-executor.0:4419 blocked for more than 143 seconds. Not tainted 5.1.0-rc4-next-20190415 #25 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D30336 4419 7846 0x00000004 Call Trace: context_switch kernel/sched/core.c:2876 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3517 schedule+0x92/0x180 kernel/sched/core.c:3561 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3619 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 __do_sys_io_uring_enter fs/io_uring.c:2679 [inline] __se_sys_io_uring_enter fs/io_uring.c:2638 [inline] __x64_sys_io_uring_enter+0x67f/0xac0 fs/io_uring.c:2638 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 0f 86 df 00 00 00 48 83 ec 30 48 89 6c 24 28 48 8d 6c 24 28 48 8b 42 08 48 8b 48 70 <48> 89 4c 24 20 48 8b 10 48 89 54 24 18 48 8b 40 08 48 89 44 24 10 RSP: 002b:00007f94bcb1fc78 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000458c29 RDX: 0000000000000000 RSI: 0000000000003f00 RDI: 0000000000000003 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f94bcb206d4 R13: 00000000004bfe3c R14: 00000000004d2120 R15: 00000000ffffffff Showing all locks held in the system: 2 locks held by kworker/u4:0/7: #0: 0000000081d6e93a (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:10053 [inline] #0: 0000000081d6e93a (&rq->lock){-.-.}, at: pick_next_task_fair+0x1214/0x19a0 kernel/sched/fair.c:7062 #1: 00000000fd5ebc74 (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:6059 1 lock held by khungtaskd/1043: #0: 00000000fd5ebc74 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5056 1 lock held by rsyslogd/7718: #0: 000000000b9abcc8 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7808: #0: 000000001d84cb26 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000051ddd853 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7809: #0: 0000000030c91f35 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000009ddf5837 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7810: #0: 00000000094d456c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000080499b98 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7811: #0: 00000000cd2ec99a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000041afa298 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7812: #0: 00000000d4a46ee9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000de95f005 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7813: #0: 00000000f0928402 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000b23a134c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7814: #0: 00000000eb3e16ea (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002100d72d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.0/4382: #0: 00000000fd000072 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_register fs/io_uring.c:2979 [inline] #0: 00000000fd000072 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_register fs/io_uring.c:2962 [inline] #0: 00000000fd000072 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_register+0x182/0x1f0 fs/io_uring.c:2962 1 lock held by syz-executor.0/4419: #0: 00000000fd000072 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_enter fs/io_uring.c:2679 [inline] #0: 00000000fd000072 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_enter fs/io_uring.c:2638 [inline] #0: 00000000fd000072 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_enter+0x67f/0xac0 fs/io_uring.c:2638 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1043 Comm: khungtaskd Not tainted 5.1.0-rc4-next-20190415 #25 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:254 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: