usb 1-1: USB disconnect, device number 2
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WARNING: CPU: 0 PID: 4651 at lib/refcount.c:28 refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28
refcount_t: underflow; use-after-free.
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 0 UID: 0 PID: 4651 Comm: kworker/0:7 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Workqueue: usb_hub_wq hub_event
Call trace: 
[<80201a24>] (dump_backtrace) from [<80201b20>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:8281f77c r5:00000000 r4:82260d04
[<80201b08>] (show_stack) from [<8021fc50>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201b08>] (show_stack) from [<8021fc50>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<8021fbfc>] (dump_stack_lvl) from [<8021fc90>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82a77d18
[<8021fc78>] (dump_stack) from [<80202624>] (vpanic+0x10c/0x30c kernel/panic.c:430)
[<80202518>] (vpanic) from [<80202858>] (trace_suspend_resume+0x0/0xd8 kernel/panic.c:566)
 r7:808bbe94
[<80202824>] (panic) from [<80254960>] (check_panic_on_warn kernel/panic.c:323 [inline])
[<80202824>] (panic) from [<80254960>] (get_taint+0x0/0x1c kernel/panic.c:318)
 r3:8280c684 r2:00000001 r1:82247720 r0:8224f19c
[<802548e8>] (check_panic_on_warn) from [<80254ac4>] (__warn+0x80/0x188 kernel/panic.c:837)
[<80254a44>] (__warn) from [<80254db4>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:872)
 r8:00000009 r7:822b9818 r6:dfc81bfc r5:848dc800 r4:00000000
[<80254bd0>] (warn_slowpath_fmt) from [<808bbe94>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:00000100 r9:829d56bc r8:854e0c88 r7:854e0074 r6:854a57b4 r5:854e0000
 r4:854a5000
[<808bbd58>] (refcount_warn_saturate) from [<81a14428>] (__refcount_sub_and_test include/linux/refcount.h:400 [inline])
[<808bbd58>] (refcount_warn_saturate) from [<81a14428>] (__refcount_dec_and_test include/linux/refcount.h:432 [inline])
[<808bbd58>] (refcount_warn_saturate) from [<81a14428>] (refcount_dec_and_test include/linux/refcount.h:450 [inline])
[<808bbd58>] (refcount_warn_saturate) from [<81a14428>] (kref_put include/linux/kref.h:64 [inline])
[<808bbd58>] (refcount_warn_saturate) from [<81a14428>] (kobject_put+0x158/0x1f4 lib/kobject.c:737)
[<81a142d0>] (kobject_put) from [<80b3d9e4>] (put_device+0x18/0x1c drivers/base/core.c:3797)
 r7:854e0074 r6:854a57b4 r5:854e0000 r4:854a5000
[<80b3d9cc>] (put_device) from [<81436e98>] (hdm_disconnect+0x98/0x9c drivers/most/most_usb.c:1130)
[<81436e00>] (hdm_disconnect) from [<80e9d084>] (usb_unbind_interface+0x84/0x2bc drivers/usb/core/driver.c:458)
 r7:854e0074 r6:854e0030 r5:00000000 r4:854e0c00
[<80e9d000>] (usb_unbind_interface) from [<80b45b60>] (device_remove drivers/base/dd.c:571 [inline])
[<80e9d000>] (usb_unbind_interface) from [<80b45b60>] (device_remove+0x64/0x6c drivers/base/dd.c:563)
 r10:00000100 r9:854e0c88 r8:00000044 r7:854e0074 r6:829d56bc r5:00000000
 r4:854e0030
[<80b45afc>] (device_remove) from [<80b47050>] (__device_release_driver drivers/base/dd.c:1274 [inline])
[<80b45afc>] (device_remove) from [<80b47050>] (device_release_driver_internal+0x18c/0x200 drivers/base/dd.c:1297)
 r5:00000000 r4:854e0030
[<80b46ec4>] (device_release_driver_internal) from [<80b470dc>] (device_release_driver+0x18/0x1c drivers/base/dd.c:1320)
 r9:854e0c88 r8:830e1040 r7:830e1038 r6:830e100c r5:854e0030 r4:830e1030
[<80b470c4>] (device_release_driver) from [<80b451a0>] (bus_remove_device+0xcc/0x120 drivers/base/bus.c:579)
[<80b450d4>] (bus_remove_device) from [<80b3f438>] (device_del+0x148/0x38c drivers/base/core.c:3878)
 r9:854e0c88 r8:848dc800 r7:04208060 r6:00000000 r5:854e0030 r4:854e0074
[<80b3f2f0>] (device_del) from [<80e9aac0>] (usb_disable_device+0xd4/0x1e8 drivers/usb/core/message.c:1418)
 r10:00000100 r9:00000000 r8:00000000 r7:854e0000 r6:854e0c00 r5:857b5708
 r4:00000001
[<80e9a9ec>] (usb_disable_device) from [<80e8f888>] (usb_disconnect+0xec/0x2ac drivers/usb/core/hub.c:2344)
 r9:84913a00 r8:854e0ccc r7:84005400 r6:854e0c88 r5:854e0c00 r4:60000013
[<80e8f79c>] (usb_disconnect) from [<80e92884>] (hub_port_connect drivers/usb/core/hub.c:5406 [inline])
[<80e8f79c>] (usb_disconnect) from [<80e92884>] (hub_port_connect_change drivers/usb/core/hub.c:5706 [inline])
[<80e8f79c>] (usb_disconnect) from [<80e92884>] (port_event drivers/usb/core/hub.c:5870 [inline])
[<80e8f79c>] (usb_disconnect) from [<80e92884>] (hub_event+0x1194/0x1950 drivers/usb/core/hub.c:5952)
 r10:00000100 r9:83d48f2c r8:84004c00 r7:854e0c00 r6:83d48800 r5:00000001
 r4:00000001
[<80e916f0>] (hub_event) from [<8027a398>] (process_one_work+0x1b4/0x4f4 kernel/workqueue.c:3236)
 r10:830e1270 r9:83265205 r8:848dc800 r7:dddced40 r6:83265200 r5:83d48f2c
 r4:84fd7780
[<8027a1e4>] (process_one_work) from [<8027afe0>] (process_scheduled_works kernel/workqueue.c:3319 [inline])
[<8027a1e4>] (process_one_work) from [<8027afe0>] (worker_thread+0x1fc/0x3d8 kernel/workqueue.c:3400)
 r10:61c88647 r9:848dc800 r8:84fd77ac r7:82804d40 r6:dddced40 r5:dddced60
 r4:84fd7780
[<8027ade4>] (worker_thread) from [<80281fcc>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r10:00000000 r9:84fd7780 r8:8027ade4 r7:df911e60 r6:84bbf280 r5:848dc800
 r4:00000001
[<80281ea0>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdfc81fb0 to 0xdfc81ff8)
1fa0:                                     00000000 00000000 00000000 00000000
1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
 r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:80281ea0
 r4:8480f980
Rebooting in 86400 seconds..