[info] Using makefile-style concurrent boot in runlevel 2. [ 15.630709][ C1] random: crng init done [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.53' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 25.976976][ T101] usb 1-1: new high-speed USB device number 2 using dummy_hcd [ 26.217396][ T101] usb 1-1: Using ep0 maxpacket: 8 [ 26.337039][ T101] usb 1-1: config 0 has an invalid interface number: 219 but max is 0 [ 26.345336][ T101] usb 1-1: config 0 has no interface number 0 [ 26.351688][ T101] usb 1-1: config 0 interface 219 altsetting 0 endpoint 0xF has an invalid bInterval 0, changing to 7 [ 26.362684][ T101] usb 1-1: config 0 interface 219 altsetting 0 endpoint 0x83 has an invalid bInterval 0, changing to 7 [ 26.374005][ T101] usb 1-1: New USB device found, idVendor=0694, idProduct=0001, bcdDevice=eb.88 [ 26.383088][ T101] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 26.392979][ T101] usb 1-1: config 0 descriptor?? [ 26.657530][ T101] legousbtower 1-1:0.219: LEGO USB Tower firmware version is 129.136 build 65535 [ 26.669645][ T101] legousbtower 1-1:0.219: LEGO USB Tower #-160 now attached to major 180 minor 0 [ 27.937160][ T1726] usb 1-1: LEGO USB Tower reset control request failed [ 27.945838][ T12] usb 1-1: USB disconnect, device number 2 [ 27.954709][ T12] [ 27.957080][ T12] ====================================================== [ 27.964071][ T12] WARNING: possible circular locking dependency detected [ 27.971184][ T12] 5.3.0+ #0 Not tainted [ 27.975307][ T12] ------------------------------------------------------ [ 27.982473][ T12] kworker/0:1/12 is trying to acquire lock: [ 27.988341][ T12] ffffffff874267c8 (minor_rwsem){++++}, at: usb_deregister_dev+0x95/0x230 [ 27.996910][ T12] [ 27.996910][ T12] but task is already holding lock: [ 28.004260][ T12] ffffffff874c5620 (open_disc_mutex){+.+.}, at: tower_disconnect+0x45/0x300 [ 28.013174][ T12] [ 28.013174][ T12] which lock already depends on the new lock. [ 28.013174][ T12] [ 28.023639][ T12] [ 28.023639][ T12] the existing dependency chain (in reverse order) is: [ 28.032629][ T12] [ 28.032629][ T12] -> #1 (open_disc_mutex){+.+.}: [ 28.039723][ T12] __mutex_lock+0x158/0x1360 [ 28.044868][ T12] tower_open+0xce/0x9b0 [ 28.049691][ T12] usb_open+0x1df/0x270 [ 28.054342][ T12] chrdev_open+0x219/0x5c0 [ 28.059351][ T12] do_dentry_open+0x494/0x1120 [ 28.064785][ T12] path_openat+0x1430/0x3f50 [ 28.069965][ T12] do_filp_open+0x1a1/0x280 [ 28.074963][ T12] do_sys_open+0x3c0/0x580 [ 28.080105][ T12] do_syscall_64+0xb7/0x580 [ 28.085157][ T12] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 28.091646][ T12] [ 28.091646][ T12] -> #0 (minor_rwsem){++++}: [ 28.098402][ T12] __lock_acquire+0x1f74/0x3eb0 [ 28.103757][ T12] lock_acquire+0x127/0x320 [ 28.108774][ T12] down_write+0x92/0x150 [ 28.113529][ T12] usb_deregister_dev+0x95/0x230 [ 28.118980][ T12] tower_disconnect+0xa8/0x300 [ 28.124252][ T12] usb_unbind_interface+0x1bd/0x8a0 [ 28.130142][ T12] device_release_driver_internal+0x42f/0x500 [ 28.136717][ T12] bus_remove_device+0x2dc/0x4a0 [ 28.142164][ T12] device_del+0x420/0xb10 [ 28.146994][ T12] usb_disable_device+0x211/0x690 [ 28.152536][ T12] usb_disconnect+0x284/0x8d0 [ 28.157910][ T12] hub_event+0x1454/0x3640 [ 28.163005][ T12] process_one_work+0x92b/0x1530 [ 28.168451][ T12] worker_thread+0x96/0xe20 [ 28.173538][ T12] kthread+0x318/0x420 [ 28.178126][ T12] ret_from_fork+0x24/0x30 [ 28.183030][ T12] [ 28.183030][ T12] other info that might help us debug this: [ 28.183030][ T12] [ 28.193343][ T12] Possible unsafe locking scenario: [ 28.193343][ T12] [ 28.200852][ T12] CPU0 CPU1 [ 28.206222][ T12] ---- ---- [ 28.211566][ T12] lock(open_disc_mutex); [ 28.216110][ T12] lock(minor_rwsem); [ 28.224351][ T12] lock(open_disc_mutex); [ 28.231536][ T12] lock(minor_rwsem); [ 28.235672][ T12] [ 28.235672][ T12] *** DEADLOCK *** [ 28.235672][ T12] [ 28.244071][ T12] 6 locks held by kworker/0:1/12: [ 28.249074][ T12] #0: ffff8881d9799ca8 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x1530 [ 28.259236][ T12] #1: ffff8881da20fdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x1530 [ 28.270152][ T12] #2: ffff8881d5ca7080 (&dev->mutex){....}, at: hub_event+0x17c/0x3640 [ 28.278811][ T12] #3: ffff8881d30e6800 (&dev->mutex){....}, at: usb_disconnect+0x91/0x8d0 [ 28.287406][ T12] #4: ffff8881d30e7010 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 [ 28.297381][ T12] #5: ffffffff874c5620 (open_disc_mutex){+.+.}, at: tower_disconnect+0x45/0x300 [ 28.306667][ T12] [ 28.306667][ T12] stack backtrace: [ 28.312549][ T12] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0+ #0 [ 28.319560][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.329700][ T12] Workqueue: usb_hub_wq hub_event [ 28.334706][ T12] Call Trace: [ 28.338063][ T12] dump_stack+0xca/0x13e [ 28.342388][ T12] check_noncircular+0x32e/0x3e0 [ 28.347425][ T12] ? save_stack+0x4c/0x80 [ 28.351733][ T12] ? print_circular_bug.isra.0+0x1e0/0x1e0 [ 28.357521][ T12] ? kobject_put+0x18c/0x280 [ 28.362086][ T12] ? usb_deregister_dev+0x89/0x230 [ 28.367197][ T12] ? tower_disconnect+0xa8/0x300 [ 28.372120][ T12] ? usb_unbind_interface+0x1bd/0x8a0 [ 28.377572][ T12] ? graph_lock+0x80/0x180 [ 28.382355][ T12] ? hlock_class+0x120/0x120 [ 28.386948][ T12] ? mark_lock+0xbc/0x1160 [ 28.391352][ T12] __lock_acquire+0x1f74/0x3eb0 [ 28.396511][ T12] ? mark_held_locks+0x9f/0xe0 [ 28.401456][ T12] ? lockdep_hardirqs_on+0x382/0x580 [ 28.406727][ T12] ? mark_held_locks+0xe0/0xe0 [ 28.411488][ T12] lock_acquire+0x127/0x320 [ 28.415982][ T12] ? usb_deregister_dev+0x95/0x230 [ 28.421222][ T12] down_write+0x92/0x150 [ 28.425533][ T12] ? usb_deregister_dev+0x95/0x230 [ 28.430622][ T12] ? __down_timeout+0x2d0/0x2d0 [ 28.435540][ T12] ? root_device_unregister+0x80/0x80 [ 28.440894][ T12] usb_deregister_dev+0x95/0x230 [ 28.445815][ T12] tower_disconnect+0xa8/0x300 [ 28.450563][ T12] usb_unbind_interface+0x1bd/0x8a0 [ 28.455736][ T12] ? usb_autoresume_device+0x60/0x60 [ 28.461035][ T12] device_release_driver_internal+0x42f/0x500 [ 28.467077][ T12] bus_remove_device+0x2dc/0x4a0 [ 28.472018][ T12] device_del+0x420/0xb10 [ 28.476348][ T12] ? __device_links_no_driver+0x240/0x240 [ 28.482042][ T12] ? usb_remove_ep_devs+0x3e/0x80 [ 28.487135][ T12] ? remove_intf_ep_devs+0x13f/0x1d0 [ 28.492392][ T12] usb_disable_device+0x211/0x690 [ 28.497391][ T12] usb_disconnect+0x284/0x8d0 [ 28.502081][ T12] hub_event+0x1454/0x3640 [ 28.506676][ T12] ? find_held_lock+0x2d/0x110 [ 28.511437][ T12] ? mark_held_locks+0xe0/0xe0 [ 28.516208][ T12] ? hub_port_debounce+0x260/0x260 [ 28.521307][ T12] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 28.526953][ T12] ? rcu_read_lock_bh_held+0xb0/0xb0 [ 28.532232][ T12] process_one_work+0x92b/0x1530 [ 28.537207][ T12] ? pwq_de