INFO: rcu_sched self-detected stall on CPU 0-....: (124998 ticks this GP) idle=36e/1/4611686018427387906 softirq=260458/260458 fqs=31225 (t=125000 jiffies g=141324 c=141323 q=1630) NMI backtrace for cpu 0 CPU: 0 PID: 22694 Comm: syz-executor4 Not tainted 4.17.0-rc7+ #72 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+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline] rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376 print_cpu_stall kernel/rcu/tree.c:1525 [inline] check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593 __rcu_pending kernel/rcu/tree.c:3356 [inline] rcu_pending kernel/rcu/tree.c:3401 [inline] rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763 update_process_times+0x2d/0x70 kernel/time/timer.c:1636 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274 __run_hrtimer kernel/time/hrtimer.c:1398 [inline] __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1460 hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 RIP: 0010:__sanitizer_cov_trace_const_cmp2+0xc/0x20 kernel/kcov.c:181 RSP: 0018:ffff880185f4f938 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 RAX: 0000000000006000 RBX: ffff8801d28f0480 RCX: dffffc0000000000 RDX: 0000000000006000 RSI: 0000000000006000 RDI: 0000000000000003 RBP: ffff880185f4f9c0 R08: ffff8801ba72a300 R09: ffffed003b5c46d2 R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000 R13: ffff8801b24c8318 R14: ffff8801b248d120 R15: ffff8801b248d040 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x9b6/0x2020 block/ioctl.c:601 block_ioctl+0xee/0x130 fs/block_dev.c:1877 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a09 RSP: 002b:00007f71787c0c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f71787c16d4 RCX: 0000000000455a09 RDX: 0000000000000013 RSI: 0000000000004c00 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002b2 R14: 00000000006f8150 R15: 0000000000000000 INFO: task syz-executor3:22699 blocked for more than 120 seconds. Not tainted 4.17.0-rc7+ #72 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D21800 22699 4558 0x80000002 Call Trace: context_switch kernel/sched/core.c:2859 [inline] __schedule+0x801/0x1e30 kernel/sched/core.c:3501 schedule+0xef/0x430 kernel/sched/core.c:3545 schedule_timeout+0x1b5/0x240 kernel/time/timer.c:1777 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+0x3e7/0x870 kernel/sched/completion.c:136 __wait_rcu_gp+0x257/0x350 kernel/rcu/update.c:414 synchronize_sched.part.64+0xe3/0xf0 kernel/rcu/tree.c:3209 synchronize_sched+0x76/0xf0 kernel/rcu/tree.c:3210 synchronize_rcu include/linux/rcupdate.h:94 [inline] synchronize_net+0x52/0x60 net/core/dev.c:8496 packet_release+0x85a/0xd60 net/packet/af_packet.c:3034 sock_release+0x96/0x1b0 net/socket.c:594 sock_close+0x16/0x20 net/socket.c:1149 __fput+0x34d/0x890 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1aee/0x2730 kernel/exit.c:865 do_group_exit+0x16f/0x430 kernel/exit.c:968 get_signal+0x886/0x1960 kernel/signal.c:2482 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810 exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath+0x516/0x5c0 arch/x86/entry/common.c:265 ret_from_fork+0x15/0x50 arch/x86/entry/entry_64.S:405 RIP: 0033:0x458399 RSP: 002b:00007f42f8432db0 EFLAGS: 00000202 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007f42f8433700 RCX: 0000000000458399 RDX: 00007f42f84339d0 RSI: 00007f42f8432db0 RDI: 00000000003d0f00 RBP: 0000000000a3e8a0 R08: 00007f42f8433700 R09: 00007f42f8433700 R10: 00007f42f84339d0 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000a3e81f R14: 00007f42f84339c0 R15: 0000000000000001 Showing all locks held in the system: 2 locks held by khungtaskd/893: #0: 00000000222e6f66 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000222e6f66 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 0000000053ac51ba (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by getty/4481: #0: 0000000083ec53c5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000096438cc5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4482: #0: 000000001adc8cf6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000efd93bbe (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4483: #0: 0000000097f9985b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ac42b0d4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4484: #0: 0000000073ad7b2c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000087149da6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4485: #0: 00000000195869a0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000005c4e5f5e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4486: #0: 00000000fdcda20c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000083390215 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4487: #0: 000000000460ff48 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000be0849a3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by syz-executor6/22719: #0: 000000007f8eaf38 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0x129f/0x2fa0 kernel/events/core.c:10475 #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: account_event kernel/events/core.c:9877 [inline] #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: perf_event_alloc.part.91+0x25c2/0x3090 kernel/events/core.c:10070 2 locks held by syz-executor0/22724: #0: 000000001eef9648 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0x129f/0x2fa0 kernel/events/core.c:10475 #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: account_event kernel/events/core.c:9877 [inline] #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: perf_event_alloc.part.91+0x25c2/0x3090 kernel/events/core.c:10070 2 locks held by syz-executor2/22744: #0: 000000009c2a35a3 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0x129f/0x2fa0 kernel/events/core.c:10475 #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: account_event kernel/events/core.c:9877 [inline] #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: perf_event_alloc.part.91+0x25c2/0x3090 kernel/events/core.c:10070 2 locks held by syz-executor5/22761: #0: 0000000096d4a2d6 (&sig->cred_guard_mutex){+.+.}, at: __do_sys_perf_event_open+0x129f/0x2fa0 kernel/events/core.c:10475 #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: account_event kernel/events/core.c:9877 [inline] #1: 00000000d7eec132 (perf_sched_mutex){+.+.}, at: perf_event_alloc.part.91+0x25c2/0x3090 kernel/events/core.c:10070 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 893 Comm: khungtaskd Not tainted 4.17.0-rc7+ #72 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+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 22694 Comm: syz-executor4 Not tainted 4.17.0-rc7+ #72 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x50 kernel/kcov.c:106 RSP: 0018:ffff880185f4f938 EFLAGS: 00000246 RAX: 0000000000040000 RBX: ffff8801d28f0480 RCX: ffffc900030c9000 RDX: 000000000003ffff RSI: ffffffff84b30851 RDI: 0000000000000003 RBP: ffff880185f4f938 R08: ffff8801ba72a300 R09: ffffed003b5c46d2 R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000 R13: ffff8801b24c8318 R14: ffff8801b248d120 R15: ffff8801b248d040 FS: 00007f71787c1700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30521000 CR3: 0000000185bd0000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: is_loop_device drivers/block/loop.c:713 [inline] loop_set_fd drivers/block/loop.c:901 [inline] lo_ioctl+0x1b71/0x2130 drivers/block/loop.c:1398 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x9b6/0x2020 block/ioctl.c:601 block_ioctl+0xee/0x130 fs/block_dev.c:1877 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a09 RSP: 002b:00007f71787c0c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f71787c16d4 RCX: 0000000000455a09 RDX: 0000000000000013 RSI: 0000000000004c00 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002b2 R14: 00000000006f8150 R15: 0000000000000000 Code: 7e 48 89 e5 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 78 12 00 00 83 fa 02 75 20 48 8b 88 80 12 00 00 8b 80 7c 12 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00