INFO: task syz-executor3:5866 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D18616 5866 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 lo_open+0x1b/0xb0 drivers/block/loop.c:1630 __blkdev_get+0x360/0x13c0 fs/block_dev.c:1482 blkdev_get+0xc1/0xb50 fs/block_dev.c:1617 blkdev_open+0x1fb/0x280 fs/block_dev.c:1775 do_dentry_open+0x499/0x1250 fs/open.c:771 vfs_open+0xa0/0xd0 fs/open.c:880 do_last fs/namei.c:3418 [inline] path_openat+0x12bc/0x5150 fs/namei.c:3534 do_filp_open+0x255/0x380 fs/namei.c:3564 do_sys_open+0x568/0x700 fs/open.c:1063 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411180 Code: Bad RIP value. RSP: 002b:00007ffc1a9b0d68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000411180 RDX: 00007ffc1a9b0dda RSI: 0000000000000002 RDI: 00007ffc1a9b0dd0 RBP: 0000000000000684 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000007 R13: 00000000000794cb R14: 00000000000001ed R15: 0000000000000003 INFO: task syz-executor5:5965 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D18584 5965 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 lo_open+0x1b/0xb0 drivers/block/loop.c:1630 __blkdev_get+0x360/0x13c0 fs/block_dev.c:1482 blkdev_get+0xc1/0xb50 fs/block_dev.c:1617 blkdev_open+0x1fb/0x280 fs/block_dev.c:1775 do_dentry_open+0x499/0x1250 fs/open.c:771 vfs_open+0xa0/0xd0 fs/open.c:880 do_last fs/namei.c:3418 [inline] path_openat+0x12bc/0x5150 fs/namei.c:3534 do_filp_open+0x255/0x380 fs/namei.c:3564 do_sys_open+0x568/0x700 fs/open.c:1063 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411180 Code: Bad RIP value. RSP: 002b:00007ffe69d45bf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000411180 RDX: 00007ffe69d45c6a RSI: 0000000000000002 RDI: 00007ffe69d45c60 RBP: 0000000000000a92 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 000000000000001c R13: 000000000007952a R14: 00000000000002e5 R15: 0000000000000005 INFO: task syz-executor1:21554 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D23784 21554 5823 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 exp_funnel_lock kernel/rcu/tree_exp.h:319 [inline] _synchronize_rcu_expedited.constprop.58+0x8df/0x9d0 kernel/rcu/tree_exp.h:620 synchronize_rcu_expedited+0x27/0xa0 kernel/rcu/tree_exp.h:758 bdi_remove_from_list mm/backing-dev.c:936 [inline] bdi_unregister+0x1bc/0x880 mm/backing-dev.c:942 del_gendisk+0x8cb/0xbb0 block/genhd.c:773 loop_remove+0x39/0xc0 drivers/block/loop.c:1926 loop_control_ioctl+0x48b/0x530 drivers/block/loop.c:2027 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007f6d5a636c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000005 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6d5a6376d4 R13: 00000000004c0631 R14: 00000000004d0a60 R15: 00000000ffffffff INFO: task syz-executor1:21556 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D25376 21556 5823 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007f6d5a615c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000004c12 RDI: 0000000000000005 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6d5a6166d4 R13: 00000000004c0606 R14: 00000000004d0a30 R15: 00000000ffffffff INFO: task syz-executor0:21555 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D23832 21555 5813 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007f5504af9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000005 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5504afa6d4 R13: 00000000004c0631 R14: 00000000004d0a60 R15: 00000000ffffffff INFO: task syz-executor0:21557 blocked for more than 140 seconds. Not tainted 4.20.0-rc1+ #105 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D24384 21557 5813 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007f5504ad8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000000004c38 RDI: 0000000000000005 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5504ad96d4 R13: 00000000004c0606 R14: 00000000004d0a30 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1007: #0: 0000000046494c60 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/5646: 2 locks held by getty/5768: #0: 00000000a423fde8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000faccc04c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5769: #0: 00000000d9762bc1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000cce26b4f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5770: #0: 0000000024ebd72b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000030f9b362 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5771: #0: 00000000c388e355 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a8331d42 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5772: #0: 00000000ed6d0575 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e8497efe (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5773: #0: 000000003acc6ac7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000189c516c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5774: #0: 000000000e9303cc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000075e59811 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by syz-executor3/5866: #0: 00000000179d5ec5 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466 #1: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: lo_open+0x1b/0xb0 drivers/block/loop.c:1630 2 locks held by syz-executor4/5920: #0: 00000000a546936c (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466 #1: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: lo_open+0x1b/0xb0 drivers/block/loop.c:1630 2 locks held by syz-executor5/5965: #0: 0000000020120fe5 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466 #1: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: lo_open+0x1b/0xb0 drivers/block/loop.c:1630 1 lock held by syz-executor1/21554: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor1/21556: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor1/21574: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor1/21575: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor0/21555: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor0/21557: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor0/21576: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 1 lock held by syz-executor0/21577: #0: 000000008b9c7e6b (loop_index_mutex){+.+.}, at: loop_control_ioctl+0x91/0x530 drivers/block/loop.c:1997 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1007 Comm: khungtaskd Not tainted 4.20.0-rc1+ #105 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57