syzbot

usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
usb 1-1: USB disconnect, device number 57
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WARNING: CPU: 1 PID: 28517 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: 1 UID: 0 PID: 28517 Comm: kworker/1:7 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)
 r7:8223c2cc r6:84b66000 r5:00000000 r4:8224dfd0
[<80201b08>] (show_stack) from [<8021f900>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201b08>] (show_stack) from [<8021f900>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120)
[<8021f8ac>] (dump_stack_lvl) from [<8021f940>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r5:00000000 r4:82a77d18
[<8021f928>] (dump_stack) from [<802025f8>] (vpanic+0xe0/0x2e8 kernel/panic.c:489)
[<80202518>] (vpanic) from [<80202834>] (trace_suspend_resume+0x0/0xd8 kernel/panic.c:626)
 r7:808cb5e8
[<80202800>] (panic) from [<80252948>] (check_panic_on_warn kernel/panic.c:376 [inline])
[<80202800>] (panic) from [<80252948>] (get_taint+0x0/0x1c kernel/panic.c:371)
 r3:8280c684 r2:00000001 r1:82234830 r0:8223c2cc
[<802528d0>] (check_panic_on_warn) from [<80252aac>] (__warn+0x80/0x188 kernel/panic.c:897)
[<80252a2c>] (__warn) from [<80252d9c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:932)
 r8:00000009 r7:822a6b8c r6:dfbb1bfc r5:84b66000 r4:00000000
[<80252bb8>] (warn_slowpath_fmt) from [<808cb5e8>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:00000100 r9:829d7a8c r8:85ede888 r7:85ede474 r6:84e6d7b4 r5:85ede400
 r4:85ae3000
[<808cb4ac>] (refcount_warn_saturate) from [<81a10868>] (__refcount_sub_and_test include/linux/refcount.h:400 [inline])
[<808cb4ac>] (refcount_warn_saturate) from [<81a10868>] (__refcount_dec_and_test include/linux/refcount.h:432 [inline])
[<808cb4ac>] (refcount_warn_saturate) from [<81a10868>] (refcount_dec_and_test include/linux/refcount.h:450 [inline])
[<808cb4ac>] (refcount_warn_saturate) from [<81a10868>] (kref_put include/linux/kref.h:64 [inline])
[<808cb4ac>] (refcount_warn_saturate) from [<81a10868>] (kobject_put+0x158/0x1f4 lib/kobject.c:737)
[<81a10710>] (kobject_put) from [<80b52848>] (put_device+0x18/0x1c drivers/base/core.c:3797)
 r7:85ede474 r6:84e6d7b4 r5:85ede400 r4:84e6d000
[<80b52830>] (put_device) from [<81457ed0>] (hdm_disconnect+0x90/0x9c drivers/most/most_usb.c:1129)
[<81457e40>] (hdm_disconnect) from [<80eb3ad8>] (usb_unbind_interface+0x84/0x2b8 drivers/usb/core/driver.c:458)
 r7:85ede474 r6:85ede430 r5:00000000 r4:85ede800
[<80eb3a54>] (usb_unbind_interface) from [<80b5a9f0>] (device_remove drivers/base/dd.c:571 [inline])
[<80eb3a54>] (usb_unbind_interface) from [<80b5a9f0>] (device_remove+0x64/0x6c drivers/base/dd.c:563)
 r10:00000100 r9:85ede888 r8:00000044 r7:85ede474 r6:829d7a8c r5:00000000
 r4:85ede430
[<80b5a98c>] (device_remove) from [<80b5bee0>] (__device_release_driver drivers/base/dd.c:1274 [inline])
[<80b5a98c>] (device_remove) from [<80b5bee0>] (device_release_driver_internal+0x18c/0x200 drivers/base/dd.c:1297)
 r5:00000000 r4:85ede430
[<80b5bd54>] (device_release_driver_internal) from [<80b5bf6c>] (device_release_driver+0x18/0x1c drivers/base/dd.c:1320)
 r9:85ede888 r8:833cfe40 r7:833cfe38 r6:833cfe0c r5:85ede430 r4:833cfe30
[<80b5bf54>] (device_release_driver) from [<80b5a030>] (bus_remove_device+0xcc/0x120 drivers/base/bus.c:579)
[<80b59f64>] (bus_remove_device) from [<80b5429c>] (device_del+0x148/0x38c drivers/base/core.c:3878)
 r9:85ede888 r8:84b66000 r7:04208060 r6:00000000 r5:85ede430 r4:85ede474
[<80b54154>] (device_del) from [<80eb13c4>] (usb_disable_device+0xd4/0x1e8 drivers/usb/core/message.c:1418)
 r10:00000100 r9:00000000 r8:00000000 r7:85ede400 r6:85ede800 r5:85f1ea08
 r4:60000113
[<80eb12f0>] (usb_disable_device) from [<80ea6134>] (usb_disconnect+0xec/0x2ac drivers/usb/core/hub.c:2344)
 r9:85ae3800 r8:85ede8cc r7:83faf400 r6:85ede888 r5:85ede800 r4:60000113
[<80ea6048>] (usb_disconnect) from [<80ea9130>] (hub_port_connect drivers/usb/core/hub.c:5406 [inline])
[<80ea6048>] (usb_disconnect) from [<80ea9130>] (hub_port_connect_change drivers/usb/core/hub.c:5706 [inline])
[<80ea6048>] (usb_disconnect) from [<80ea9130>] (port_event drivers/usb/core/hub.c:5870 [inline])
[<80ea6048>] (usb_disconnect) from [<80ea9130>] (hub_event+0x1194/0x1950 drivers/usb/core/hub.c:5952)
 r10:00000100 r9:83d8172c r8:83faec00 r7:85ede800 r6:83d81000 r5:00000001
 r4:00000001
[<80ea7f9c>] (hub_event) from [<80278594>] (process_one_work+0x1b4/0x4f4 kernel/workqueue.c:3263)
 r10:833d5070 r9:83272e05 r8:84b66000 r7:ddde3d80 r6:83272e00 r5:83d8172c
 r4:85cf5a80
[<802783e0>] (process_one_work) from [<802791dc>] (process_scheduled_works kernel/workqueue.c:3346 [inline])
[<802783e0>] (process_one_work) from [<802791dc>] (worker_thread+0x1fc/0x3d8 kernel/workqueue.c:3427)
 r10:61c88647 r9:84b66000 r8:85cf5aac r7:82804d40 r6:ddde3d80 r5:ddde3da0
 r4:85cf5a80
[<80278fe0>] (worker_thread) from [<80280200>] (kthread+0x12c/0x280 kernel/kthread.c:463)
 r10:00000000 r9:85cf5a80 r8:80278fe0 r7:dfbade60 r6:85d01200 r5:84b66000
 r4:00000001
[<802800d4>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137)
Exception stack(0xdfbb1fb0 to 0xdfbb1ff8)
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 r5:802800d4
 r4:85c82680
Rebooting in 86400 seconds..