------------[ cut here ]------------
URB 00000000b4e44ac2 submitted while active
WARNING: CPU: 0 PID: 12 at drivers/usb/core/urb.c:363 usb_submit_urb+0x11cf/0x14e0 drivers/usb/core/urb.c:363
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 4.20.0-rc6+ #371
kobject: 'loop2' (00000000e0df4b29): kobject_uevent_env
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient hub_init_func2
Call Trace:
kobject: 'loop2' (00000000e0df4b29): fill_kobj_path: path = '/devices/virtual/block/loop2'
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
kobject: 'loop3' (000000004b7a892a): kobject_uevent_env
kobject: 'loop3' (000000004b7a892a): fill_kobj_path: path = '/devices/virtual/block/loop3'
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
kobject: 'loop4' (00000000a0265ef2): kobject_uevent_env
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
kobject: 'loop4' (00000000a0265ef2): fill_kobj_path: path = '/devices/virtual/block/loop4'
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:usb_submit_urb+0x11cf/0x14e0 drivers/usb/core/urb.c:363
Code: ee e8 f5 ee 6f fc 45 84 ed 0f 85 e2 f6 ff ff e8 17 ee 6f fc 48 89 de 48 c7 c7 00 07 94 88 c6 05 b7 31 03 05 01 e8 11 4e 39 fc <0f> 0b e9 c0 f6 ff ff c7 45 a0 01 00 00 00 e9 65 f7 ff ff 41 bc ed
RSP: 0018:ffff8881d9b1f4f0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881c5c7e400 RCX: 0000000000000000
kobject: 'loop1' (000000005cf78b3c): kobject_uevent_env
RDX: 0000000000000000 RSI: ffffffff8165e495 RDI: 0000000000000005
RBP: ffff8881d9b1f560 R08: ffff8881d9b12300 R09: ffffed103b5c3ef8
R10: ffffed103b5c3ef8 R11: ffff8881dae1f7c7 R12: 00000000fffffff0
R13: 0000000000000000 R14: 0000000000000009 R15: ffff8881d9b1f6f8
 hub_activate+0xcab/0x1940 drivers/usb/core/hub.c:1215
kobject: 'loop1' (000000005cf78b3c): fill_kobj_path: path = '/devices/virtual/block/loop1'
 hub_init_func2+0x1e/0x30 drivers/usb/core/hub.c:1240
 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
kobject: 'loop2' (00000000e0df4b29): kobject_uevent_env
kobject: 'loop2' (00000000e0df4b29): fill_kobj_path: path = '/devices/virtual/block/loop2'
 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
kobject: 'loop3' (000000004b7a892a): kobject_uevent_env
kobject: 'loop3' (000000004b7a892a): fill_kobj_path: path = '/devices/virtual/block/loop3'
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..