INFO: task syz-executor.2:8759 blocked for more than 143 seconds. Not tainted 5.1.0-rc5-next-20190418 #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D27544 8759 7761 0x00004004 Call Trace: context_switch kernel/sched/core.c:2817 [inline] __schedule+0x7d1/0x15c0 kernel/sched/core.c:3444 schedule+0xa8/0x260 kernel/sched/core.c:3508 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+0x103/0x670 arch/x86/entry/common.c:298 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007fc887366c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458c29 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc8873676d4 R13: 00000000004cb6c8 R14: 00000000004d2150 R15: 00000000ffffffff INFO: task syz-executor.2:8764 blocked for more than 143 seconds. Not tainted 5.1.0-rc5-next-20190418 #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D30040 8764 7761 0x00000004 Call Trace: context_switch kernel/sched/core.c:2817 [inline] __schedule+0x7d1/0x15c0 kernel/sched/core.c:3444 schedule+0xa8/0x260 kernel/sched/core.c:3508 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3567 __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+0x103/0x670 arch/x86/entry/common.c:298 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007fc887345c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000458c29 RDX: 00000000000000a1 RSI: 0000000000000008 RDI: 0000000000000003 RBP: 000000000073bfa0 R08: 0000000020000280 R09: 0000000000000008 R10: 0000000000000001 R11: 0000000000000246 R12: 00007fc8873466d4 R13: 00000000004bfe3c R14: 00000000004d2120 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1043: #0: 0000000026a32355 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5046 2 locks held by getty/7719: #0: 000000003a040f41 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f78f8316 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7720: #0: 0000000081d7dbc8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000add0dd31 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7721: #0: 0000000044d3b73b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000fbd9170c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7722: #0: 00000000a22cf5e6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000058d63a70 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7723: #0: 00000000aad2c746 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000006ab8a342 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7724: #0: 000000000e508fe1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000e26800f1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7725: #0: 000000007c7f1c27 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000036b1ecf7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.2/8759: #0: 000000005cf341d5 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_register fs/io_uring.c:2979 [inline] #0: 000000005cf341d5 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_register fs/io_uring.c:2962 [inline] #0: 000000005cf341d5 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_register+0x182/0x1f0 fs/io_uring.c:2962 1 lock held by syz-executor.2/8764: #0: 000000005cf341d5 (&ctx->uring_lock){+.+.}, at: __do_sys_io_uring_enter fs/io_uring.c:2679 [inline] #0: 000000005cf341d5 (&ctx->uring_lock){+.+.}, at: __se_sys_io_uring_enter fs/io_uring.c:2638 [inline] #0: 000000005cf341d5 (&ctx->uring_lock){+.+.}, at: __x64_sys_io_uring_enter+0x67f/0xac0 fs/io_uring.c:2638 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1043 Comm: khungtaskd Not tainted 5.1.0-rc5-next-20190418 #28 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 1 to CPUs 0: