Re: WARNING in rollback_registered_many (2)

[syzbot]

syzbot has found a reproducer for 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=10d552b7200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
dashboard link: https://syzkaller.appspot.com/bug?extid=40918e4d826fb2ff9b96
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17a4c1af200000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=121b274b200000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+40918e4d826fb2ff9b96@xxxxxxxxxxxxxxxxxxxxxxxxx

usb 1-1: r8712u: MAC Address from efuse = 00:e0:4c:87:00:00
usb 1-1: r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
usb 1-1: USB disconnect, device number 2
usb 1-1: Direct firmware load for rtlwifi/rtl8712u.bin failed with error -2
usb 1-1: r8712u: Firmware request failed
WARNING: CPU: 0 PID: 575 at net/core/dev.c:8152  
rollback_registered_many+0x1f3/0xe70 net/core/dev.c:8152
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 575 Comm: kworker/0:4 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:rollback_registered_many+0x1f3/0xe70 net/core/dev.c:8152
Code: 05 00 00 31 ff 44 89 fe e8 5a 15 f3 f4 45 84 ff 0f 85 49 ff ff ff e8  
1c 14 f3 f4 0f 1f 44 00 00 e8 12 14 f3 f4 e8 0d 14 f3 f4 <0f> 0b 4c 89 e7  
e8 33 72 f2 f6 31 ff 41 89 c4 89 c6 e8 27 15 f3 f4
RSP: 0018:ffff88809d087698 EFLAGS: 00010293
RAX: ffff88809d058000 RBX: ffff888096240000 RCX: ffffffff8c7eb146
RDX: 0000000000000000 RSI: ffffffff8c7eb163 RDI: 0000000000000001
RBP: ffff88809d0877c8 R08: ffff88809d058000 R09: fffffbfff2708111
R10: fffffbfff2708110 R11: ffffffff93840887 R12: ffff888096240070
R13: dffffc0000000000 R14: ffff88809d087758 R15: 0000000000000000
 rollback_registered+0xf7/0x1c0 net/core/dev.c:8228
 unregister_netdevice_queue net/core/dev.c:9275 [inline]
 unregister_netdevice_queue+0x1dc/0x2b0 net/core/dev.c:9268
 unregister_netdevice include/linux/netdevice.h:2655 [inline]
 unregister_netdev+0x1d/0x30 net/core/dev.c:9316
 r871xu_dev_remove+0xe7/0x223 drivers/staging/rtl8712/usb_intf.c:604
 usb_unbind_interface+0x1c9/0x980 drivers/usb/core/driver.c:423
 __device_release_driver drivers/base/dd.c:1082 [inline]
 device_release_driver_internal+0x436/0x4f0 drivers/base/dd.c:1113
 bus_remove_device+0x302/0x5c0 drivers/base/bus.c:556
 device_del+0x467/0xb90 drivers/base/core.c:2269
 usb_disable_device+0x242/0x790 drivers/usb/core/message.c:1235
 usb_disconnect+0x298/0x870 drivers/usb/core/hub.c:2197
 hub_port_connect drivers/usb/core/hub.c:4940 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
 port_event drivers/usb/core/hub.c:5350 [inline]
 hub_event+0xcd2/0x3b00 drivers/usb/core/hub.c:5432
 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
 process_scheduled_works kernel/workqueue.c:2331 [inline]
 worker_thread+0x7b0/0xe20 kernel/workqueue.c:2417
 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..