INFO: task kworker/0:5:4538 blocked for more than 143 seconds. Not tainted 5.6.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:5 D23760 4538 2 0x80004000 Workqueue: usb_hub_wq hub_event Call Trace: schedule+0xcd/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x682/0xb20 kernel/time/timer.c:1871 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+0x26f/0x3c0 kernel/sched/completion.c:136 kthread_stop+0x17a/0x780 kernel/kthread.c:559 hwrng_unregister+0x24f/0x330 drivers/char/hw_random/core.c:556 chaoskey_disconnect+0x216/0x290 drivers/usb/misc/chaoskey.c:232 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:436 __device_release_driver drivers/base/dd.c:1137 [inline] device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1168 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533 device_del+0x481/0xd30 drivers/base/core.c:2677 usb_disable_device+0x23d/0x790 drivers/usb/core/message.c:1237 usb_disconnect+0x293/0x900 drivers/usb/core/hub.c:2211 hub_port_connect drivers/usb/core/hub.c:5046 [inline] hub_port_connect_change drivers/usb/core/hub.c:5335 [inline] port_event drivers/usb/core/hub.c:5481 [inline] hub_event+0x1a1d/0x4300 drivers/usb/core/hub.c:5563 process_one_work+0x94b/0x1620 kernel/workqueue.c:2264 worker_thread+0x96/0xe20 kernel/workqueue.c:2410 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 4 locks held by kworker/1:0/17: 1 lock held by khungtaskd/23: #0: ffffffff87109060 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/1675: #0: ffff8881d0db40e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/1764: #0: ffff8881cee60090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000084f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1765: #0: ffff8881cef99090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000085f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1766: #0: ffff8881d1cb4090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000086f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1767: #0: ffff8881cece3090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008572e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1768: #0: ffff8881d1cb3090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000086b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1769: #0: ffff8881cf2cd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000084b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1770: #0: ffff8881cf2cb090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008372e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 6 locks held by kworker/1:3/4533: #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881c7627dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4877200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4877200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5509 #3: ffff8881cee66200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881cee66200 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874 #4: ffff8881cb83a190 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #4: ffff8881cb83a190 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874 #5: ffff8881c72fabd0 (&dev->phy_mutex){+.+.}, at: mcs7830_write_phy+0x9e/0x280 drivers/net/usb/mcs7830.c:218 5 locks held by kworker/0:5/4538: #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881ac55fdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d495c200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d495c200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5509 #3: ffff8881ccc37200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881ccc37200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2202 #4: ffff8881adec8190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1165 6 locks held by kworker/1:5/4777: #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881ce3b7dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d499a200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d499a200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5509 #3: ffff8881d499c540 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:3008 [inline] #3: ffff8881d499c540 (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5126 [inline] #3: ffff8881d499c540 (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5335 [inline] #3: ffff8881d499c540 (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5481 [inline] #3: ffff8881d499c540 (&port_dev->status_lock){+.+.}, at: hub_event+0x1fae/0x4300 drivers/usb/core/hub.c:5563 #4: ffff8881d4ef8760 (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1b6/0x2e60 drivers/usb/core/hub.c:4550 #5: ffffffff8767fb08 (ehci_cf_port_reset_rwsem){.+.+}, at: hub_port_reset+0x186/0x1790 drivers/usb/core/hub.c:2870 5 locks held by kworker/0:8/5397: #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8861928 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881d2957dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d48f5200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d48f5200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5509 #3: ffff8881d48f7540 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:3008 [inline] #3: ffff8881d48f7540 (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5126 [inline] #3: ffff8881d48f7540 (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5335 [inline] #3: ffff8881d48f7540 (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5481 [inline] #3: ffff8881d48f7540 (&port_dev->status_lock){+.+.}, at: hub_event+0x1fae/0x4300 drivers/usb/core/hub.c:5563 #4: ffff8881d4ef8160 (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1b6/0x2e60 drivers/usb/core/hub.c:4550 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 5.6.0-rc5-syzkaller #0 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+0xef/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1db/0x207 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa99/0xfd0 kernel/hung_task.c:289 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5397 Comm: kworker/0:8 Not tainted 5.6.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event RIP: 0010:__lock_acquire+0x10b4/0x3b60 kernel/locking/lockdep.c:3827 Code: 1e 00 00 48 81 c4 e8 00 00 00 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 80 3c 02 00 <0f> 85 db 20 00 00 49 81 3e 60 10 c2 88 0f 84 11 f0 ff ff 83 fe 01 RSP: 0018:ffff8881d2957720 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 1ffffffff12f6c80 RSI: 0000000000000000 RDI: ffffffff897b6400 RBP: ffff8881d3500000 R08: 0000000000000001 R09: 0000000000000001 R10: fffffbfff0fcc0f8 R11: ffffffff87e607c7 R12: 0000000000000001 R13: 0000000000000000 R14: ffffffff897b6400 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdb41dc7c10 CR3: 00000001cc1e9000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x130/0x340 kernel/locking/lockdep.c:4484 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x32/0x50 kernel/locking/spinlock.c:159 __debug_check_no_obj_freed lib/debugobjects.c:955 [inline] debug_check_no_obj_freed+0xc4/0x445 lib/debugobjects.c:998 slab_free_hook mm/slub.c:1441 [inline] slab_free_freelist_hook mm/slub.c:1477 [inline] slab_free mm/slub.c:3024 [inline] kfree+0x18a/0x300 mm/slub.c:3976 usb_control_msg+0x393/0x4a0 drivers/usb/core/message.c:158 hub_port_init+0x884/0x2e60 drivers/usb/core/hub.c:4676 hub_port_connect drivers/usb/core/hub.c:5127 [inline] hub_port_connect_change drivers/usb/core/hub.c:5335 [inline] port_event drivers/usb/core/hub.c:5481 [inline] hub_event+0x1fc6/0x4300 drivers/usb/core/hub.c:5563 process_one_work+0x94b/0x1620 kernel/workqueue.c:2264 worker_thread+0x96/0xe20 kernel/workqueue.c:2410 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352