usb 1-1: USB disconnect, device number 15 ====================================================== WARNING: possible circular locking dependency detected 5.3.0-rc2+ #25 Not tainted ------------------------------------------------------ kworker/1:5/2764 is trying to acquire lock: 000000001664f143 (minor_rwsem){++++}, at: usb_deregister_dev drivers/usb/core/file.c:238 [inline] 000000001664f143 (minor_rwsem){++++}, at: usb_deregister_dev+0x61/0x270 drivers/usb/core/file.c:230 but task is already holding lock: 00000000733572d0 (iowarrior_open_disc_lock){+.+.}, at: iowarrior_disconnect+0x45/0x2c0 drivers/usb/misc/iowarrior.c:867 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (iowarrior_open_disc_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:930 [inline] __mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077 iowarrior_open+0x8a/0x2a0 drivers/usb/misc/iowarrior.c:600 usb_open+0x1df/0x270 drivers/usb/core/file.c:48 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 do_dentry_open+0x494/0x1120 fs/open.c:797 do_last fs/namei.c:3416 [inline] path_openat+0x1430/0x3f50 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3c0/0x580 fs/open.c:1089 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (iowarrior_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:930 [inline] __mutex_lock+0x158/0x1360 kernel/locking/mutex.c:1077 iowarrior_open+0x23/0x2a0 drivers/usb/misc/iowarrior.c:589 usb_open+0x1df/0x270 drivers/usb/core/file.c:48 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 do_dentry_open+0x494/0x1120 fs/open.c:797 do_last fs/namei.c:3416 [inline] path_openat+0x1430/0x3f50 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3c0/0x580 fs/open.c:1089 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (minor_rwsem){++++}: check_prev_add kernel/locking/lockdep.c:2405 [inline] check_prevs_add kernel/locking/lockdep.c:2507 [inline] validate_chain kernel/locking/lockdep.c:2897 [inline] __lock_acquire+0x1f7c/0x3b50 kernel/locking/lockdep.c:3880 lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412 down_write+0x92/0x150 kernel/locking/rwsem.c:1500 usb_deregister_dev drivers/usb/core/file.c:238 [inline] usb_deregister_dev+0x61/0x270 drivers/usb/core/file.c:230 iowarrior_disconnect+0xa8/0x2c0 drivers/usb/misc/iowarrior.c:873 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 __device_release_driver drivers/base/dd.c:1120 [inline] device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151 bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556 device_del+0x420/0xb10 drivers/base/core.c:2288 usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199 hub_port_connect drivers/usb/core/hub.c:4949 [inline] hub_port_connect_change drivers/usb/core/hub.c:5213 [inline] port_event drivers/usb/core/hub.c:5359 [inline] hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 worker_thread+0x96/0xe20 kernel/workqueue.c:2415 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 other info that might help us debug this: Chain exists of: minor_rwsem --> iowarrior_mutex --> iowarrior_open_disc_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(iowarrior_open_disc_lock); lock(iowarrior_mutex); lock(iowarrior_open_disc_lock); lock(minor_rwsem); *** DEADLOCK *** 6 locks held by kworker/1:5/2764: #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: 00000000655bb834 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x1530 kernel/workqueue.c:2240 #1: 00000000a62717b4 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x1530 kernel/workqueue.c:2244 #2: 00000000ff6162a8 (&dev->mutex){....}, at: device_lock include/linux/device.h:1220 [inline] #2: 00000000ff6162a8 (&dev->mutex){....}, at: hub_event+0x17c/0x3640 drivers/usb/core/hub.c:5387 #3: 00000000a6e8a370 (&dev->mutex){....}, at: device_lock include/linux/device.h:1220 [inline] #3: 00000000a6e8a370 (&dev->mutex){....}, at: usb_disconnect+0x91/0x8d0 drivers/usb/core/hub.c:2190 #4: 000000006bc073e8 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x4c0 drivers/base/dd.c:1148 #5: 00000000733572d0 (iowarrior_open_disc_lock){+.+.}, at: iowarrior_disconnect+0x45/0x2c0 drivers/usb/misc/iowarrior.c:867 stack backtrace: CPU: 1 PID: 2764 Comm: kworker/1:5 Not tainted 5.3.0-rc2+ #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xca/0x13e lib/dump_stack.c:113 check_noncircular+0x345/0x3e0 kernel/locking/lockdep.c:1741 check_prev_add kernel/locking/lockdep.c:2405 [inline] check_prevs_add kernel/locking/lockdep.c:2507 [inline] validate_chain kernel/locking/lockdep.c:2897 [inline] __lock_acquire+0x1f7c/0x3b50 kernel/locking/lockdep.c:3880 lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412 down_write+0x92/0x150 kernel/locking/rwsem.c:1500 usb_deregister_dev drivers/usb/core/file.c:238 [inline] usb_deregister_dev+0x61/0x270 drivers/usb/core/file.c:230 iowarrior_disconnect+0xa8/0x2c0 drivers/usb/misc/iowarrior.c:873 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 __device_release_driver drivers/base/dd.c:1120 [inline] device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151 bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556 device_del+0x420/0xb10 drivers/base/core.c:2288 usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199 hub_port_connect drivers/usb/core/hub.c:4949 [inline] hub_port_connect_change drivers/usb/core/hub.c:5213 [inline] port_event drivers/usb/core/hub.c:5359 [inline] hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 worker_thread+0x96/0xe20 kernel/workqueue.c:2415 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 iowarrior 1-1:0.236: I/O-Warror #0 now disconnected usb 6-1: USB disconnect, device number 31 xpad 6-1:0.65: xpad_try_sending_next_out_packet - usb_submit_urb failed with result -19 usb 4-1: USB disconnect, device number 24 cdc_subset 4-1:0.109 usb0: unregister 'cdc_subset' usb-dummy_hcd.3-1, AnchorChips/Cypress 2720 usb 3-1: new full-speed USB device number 21 using dummy_hcd usb 3-1: config 1 interface 0 altsetting 0 has 1 endpoint descriptor, different from the interface descriptor's value: 9 usb 3-1: New USB device found, idVendor=0525, idProduct=a4a8, bcdDevice= 0.40 usb 3-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0