WARNING in __flush_work (3)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 9a33b369 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan/tree/usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=17f389af200000
kernel config: https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
dashboard link: https://syzkaller.appspot.com/bug?extid=2e1ef9188251d9cc7944
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10dd0fc3200000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e77a5b200000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2e1ef9...@syzkaller.appspotmail.com

usb 1-1: config 0 has an invalid interface number: 246 but max is 0
usb 1-1: config 0 has no interface number 0
usb 1-1: New USB device found, idVendor=06f8, idProduct=300c,
bcdDevice=68.91
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3030 __flush_work+0x728/0x820
kernel/workqueue.c:3030
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.1.0-rc4-319354-g9a33b36 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xe8/0x16e lib/dump_stack.c:113
panic+0x29d/0x5f2 kernel/panic.c:214
__warn.cold+0x20/0x48 kernel/panic.c:571
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x130/0x1f0 arch/x86/kernel/traps.c:272
do_invalid_op+0x37/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:__flush_work+0x728/0x820 kernel/workqueue.c:3030
Code: ff e8 3c 37 27 00 0f 0b 45 31 e4 e9 7e fd ff ff e8 2d 37 27 00 4c 89
ef 45 31 e4 e8 f2 a6 bb 0c e9 69 fd ff ff e8 18 37 27 00 <0f> 0b 45 31 e4
e9 5a fd ff ff e8 b9 47 5e 00 e9 78 fc ff ff e8 cf
RSP: 0018:ffff8880a84b6e48 EFLAGS: 00010293
RAX: ffff8880a84a3100 RBX: ffff888091a6fcb0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff814a8e58 RDI: 0000000000000001
RBP: ffff8880a84b6fb0 R08: ffff8880a84a3100 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000001 R14: 0000000000000200 R15: ffff888091a6fcc8
__cancel_work_timer+0x326/0x450 kernel/workqueue.c:3126
uvc_ctrl_cleanup_device+0x27/0x488 drivers/media/usb/uvc/uvc_ctrl.c:2353
uvc_delete+0x2e/0x2f0 drivers/media/usb/uvc/uvc_driver.c:1871
kref_put include/linux/kref.h:67 [inline]
uvc_probe+0xfa5/0x6588 drivers/media/usb/uvc/uvc_driver.c:2228
usb_probe_interface+0x31d/0x820 drivers/usb/core/driver.c:361
really_probe+0x2da/0xb10 drivers/base/dd.c:509
driver_probe_device+0x21d/0x350 drivers/base/dd.c:671
__device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778
bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454
__device_attach+0x223/0x3a0 drivers/base/dd.c:844
bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514
device_add+0xad2/0x16e0 drivers/base/core.c:2106
usb_set_configuration+0xdf7/0x1740 drivers/usb/core/message.c:2021
generic_probe+0xa2/0xda drivers/usb/core/generic.c:210
usb_probe_device+0xc0/0x150 drivers/usb/core/driver.c:266
really_probe+0x2da/0xb10 drivers/base/dd.c:509
driver_probe_device+0x21d/0x350 drivers/base/dd.c:671
__device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778
bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454
__device_attach+0x223/0x3a0 drivers/base/dd.c:844
bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514
device_add+0xad2/0x16e0 drivers/base/core.c:2106
usb_new_device.cold+0x537/0xccf drivers/usb/core/hub.c:2534
hub_port_connect drivers/usb/core/hub.c:5089 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
port_event drivers/usb/core/hub.c:5350 [inline]
hub_event+0x138e/0x3b00 drivers/usb/core/hub.c:5432
process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
kthread+0x313/0x420 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..


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