usb 2-1: USB disconnect, device number 67 ====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Not tainted ------------------------------------------------------ kworker/0:1/9 is trying to acquire lock: ffffffff899dadb0 (minor_rwsem){++++}-{3:3}, at: usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186 but task is already holding lock: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_disconnect+0xa8/0x2a0 drivers/usb/misc/chaoskey.c:235 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (chaoskey_list_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 chaoskey_open+0xdd/0x220 drivers/usb/misc/chaoskey.c:274 usb_open+0x186/0x220 drivers/usb/core/file.c:47 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6cb/0x1390 fs/open.c:958 vfs_open+0x82/0x3f0 fs/open.c:1088 do_open fs/namei.c:3774 [inline] path_openat+0x1e6a/0x2d60 fs/namei.c:3933 do_filp_open+0x1dc/0x430 fs/namei.c:3960 do_sys_openat2+0x17a/0x1e0 fs/open.c:1415 do_sys_open fs/open.c:1430 [inline] __do_sys_openat fs/open.c:1446 [inline] __se_sys_openat fs/open.c:1441 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1441 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (minor_rwsem){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825 down_write+0x93/0x200 kernel/locking/rwsem.c:1577 usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186 chaoskey_disconnect+0xb7/0x2a0 drivers/usb/misc/chaoskey.c:236 usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461 device_remove drivers/base/dd.c:569 [inline] device_remove+0x122/0x170 drivers/base/dd.c:561 __device_release_driver drivers/base/dd.c:1273 [inline] device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1296 bus_remove_device+0x22f/0x420 drivers/base/bus.c:576 device_del+0x396/0x9f0 drivers/base/core.c:3864 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418 usb_disconnect+0x2e1/0x920 drivers/usb/core/hub.c:2304 hub_port_connect drivers/usb/core/hub.c:5361 [inline] hub_port_connect_change drivers/usb/core/hub.c:5661 [inline] port_event drivers/usb/core/hub.c:5821 [inline] hub_event+0x1bed/0x4f40 drivers/usb/core/hub.c:5903 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(chaoskey_list_lock); lock(minor_rwsem); lock(chaoskey_list_lock); lock(minor_rwsem); *** DEADLOCK *** 6 locks held by kworker/0:1/9: #0: ffff888105efad48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x129b/0x1ba0 kernel/workqueue.c:3204 #1: ffffc9000009fd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3205 #2: ffff888107f82190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline] #2: ffff888107f82190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5849 #3: ffff888131f74190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline] #3: ffff888131f74190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10a/0x920 drivers/usb/core/hub.c:2295 #4: ffff8881153be160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline] #4: ffff8881153be160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline] #4: ffff8881153be160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1293 #5: ffffffff89b120e8 (chaoskey_list_lock){+.+.}-{3:3}, at: chaoskey_disconnect+0xa8/0x2a0 drivers/usb/misc/chaoskey.c:235 stack backtrace: CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.12.0-rc1-syzkaller-00027-g4a9fe2a8ac53 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825 down_write+0x93/0x200 kernel/locking/rwsem.c:1577 usb_deregister_dev+0x7c/0x1e0 drivers/usb/core/file.c:186 chaoskey_disconnect+0xb7/0x2a0 drivers/usb/misc/chaoskey.c:236 usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461 device_remove drivers/base/dd.c:569 [inline] device_remove+0x122/0x170 drivers/base/dd.c:561 __device_release_driver drivers/base/dd.c:1273 [inline] device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1296 bus_remove_device+0x22f/0x420 drivers/base/bus.c:576 device_del+0x396/0x9f0 drivers/base/core.c:3864 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1418 usb_disconnect+0x2e1/0x920 drivers/usb/core/hub.c:2304 hub_port_connect drivers/usb/core/hub.c:5361 [inline] hub_port_connect_change drivers/usb/core/hub.c:5661 [inline] port_event drivers/usb/core/hub.c:5821 [inline] hub_event+0x1bed/0x4f40 drivers/usb/core/hub.c:5903 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 usb 4-1: USB disconnect, device number 60