udc dummy_udc.1: failed to start USB Gadget filesystem: -12
gadgetfs gadget.1: probe with driver gadgetfs failed with error -12
UDC core: USB Gadget filesystem: couldn't find an available UDC
------------[ cut here ]------------
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x134/0x170 lib/refcount.c:28, CPU#0: syz.2.17/4036
refcount_t: underflow; use-after-free.
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 0 UID: 0 PID: 4036 Comm: syz.2.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: ARM-Versatile Express
Call trace: 
[<80201998>] (dump_backtrace) from [<80201a8c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:82a20f78 r6:00000000 r5:82333190 r4:00000001
[<80201a74>] (show_stack) from [<8021e60c>] (__dump_stack lib/dump_stack.c:94 [inline])
[<80201a74>] (show_stack) from [<8021e60c>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120)
[<8021e5b0>] (dump_stack_lvl) from [<8021e638>] (dump_stack+0x18/0x1c lib/dump_stack.c:129)
 r7:82a20f78 r6:00000000 r5:83e0c980 r4:82c83d40
[<8021e620>] (dump_stack) from [<80202590>] (vpanic+0x114/0x320 kernel/panic.c:651)
[<8020247c>] (vpanic) from [<802027d0>] (trace_suspend_resume+0x0/0x100 kernel/panic.c:788)
 r7:809300ec
[<8020279c>] (panic) from [<80250a80>] (check_panic_on_warn kernel/panic.c:525 [inline])
[<8020279c>] (panic) from [<80250a80>] (get_taint+0x0/0x1c kernel/panic.c:520)
 r3:82a0b144 r2:00000001 r1:82318ef4 r0:82320850
[<80250a08>] (check_panic_on_warn) from [<80250bfc>] (__warn+0x98/0x1a4 kernel/panic.c:1104)
[<80250b64>] (__warn) from [<80250ef0>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:1144)
 r8:00000009 r7:8238cee4 r6:e0259da4 r5:83e0c980 r4:00000000
[<80250d0c>] (warn_slowpath_fmt) from [<809300ec>] (refcount_warn_saturate+0x134/0x170 lib/refcount.c:28)
 r10:8475ea00 r9:00000000 r8:838acb10 r7:8553bc80 r6:835f77f8 r5:00000000
 r4:85c7f600
[<8092ffb8>] (refcount_warn_saturate) from [<81120650>] (__refcount_sub_and_test include/linux/refcount.h:400 [inline])
[<8092ffb8>] (refcount_warn_saturate) from [<81120650>] (__refcount_dec_and_test include/linux/refcount.h:432 [inline])
[<8092ffb8>] (refcount_warn_saturate) from [<81120650>] (refcount_dec_and_test include/linux/refcount.h:450 [inline])
[<8092ffb8>] (refcount_warn_saturate) from [<81120650>] (put_dev+0x4c/0x6c drivers/usb/gadget/legacy/inode.c:165)
[<81120604>] (put_dev) from [<81120718>] (dev_release+0x48/0x6c drivers/usb/gadget/legacy/inode.c:1215)
[<811206d0>] (dev_release) from [<805a1bcc>] (__fput+0xd8/0x2f4 fs/file_table.c:512)
 r5:040f801b r4:85a2ef00
[<805a1af4>] (__fput) from [<805a1e7c>] (____fput+0x14/0x18 fs/file_table.c:540)
 r9:00000000 r8:83e0d214 r7:82c846ac r6:83e0c980 r5:83e0d1e0 r4:00000000
[<805a1e68>] (____fput) from [<8027d7c8>] (task_work_run+0x8c/0xb4 kernel/task_work.c:233)
[<8027d73c>] (task_work_run) from [<80257888>] (exit_task_work include/linux/task_work.h:40 [inline])
[<8027d73c>] (task_work_run) from [<80257888>] (do_exit+0x2ac/0xadc kernel/exit.c:1009)
 r9:00000000 r8:e0259e90 r7:83e0d210 r6:850c5d4c r5:83e0c980 r4:850c5c00
[<802575dc>] (do_exit) from [<8025828c>] (do_group_exit+0x40/0x8c kernel/exit.c:1152)
 r7:00000004
[<8025824c>] (do_group_exit) from [<80269358>] (get_signal+0xa68/0xa90 kernel/signal.c:3046)
 r7:00000004 r4:83e0c980
[<802688f0>] (get_signal) from [<8022a630>] (do_signal arch/arm/kernel/signal.c:579 [inline])
[<802688f0>] (get_signal) from [<8022a630>] (do_work_pending+0x124/0x4f0 arch/arm/kernel/signal.c:619)
 r10:00000004 r9:83e0c980 r8:0000001f r7:00000004 r6:8020029c r5:e0259fb0
 r4:83e0c980
[<8022a50c>] (do_work_pending) from [<80200088>] (slow_work_pending+0xc/0x24)
Exception stack(0xe0259fb0 to 0xe0259ff8)
9fa0:                                     0000001f 20000400 0000001f 00000000
9fc0: 00000000 00000000 00356310 00000004 003562d8 00000000 003562d8 003562e4
9fe0: 7ef7e798 7ef7e788 00018fa0 001309d0 60000010 00000003
 r10:00000004 r9:83e0c980 r8:8020029c r7:00000004 r6:00356310 r5:00000000
 r4:00000000
Rebooting in 86400 seconds..