KASAN: use-after-free Read in mcba_usb_disconnect

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 2994c077 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=173b5acd600000
kernel config: https://syzkaller.appspot.com/x/.config?x=69ddefac6929256a
dashboard link: https://syzkaller.appspot.com/bug?extid=e29b17e5042bbc56fae9
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10ec8e19600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=107ad813600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e29b17...@syzkaller.appspotmail.com

mcba_usb 1-1:0.180 can1: Failed to send cmd (169)
mcba_usb 1-1:0.180: Microchip CAN BUS Analyzer connected
usb 1-1: USB disconnect, device number 2
mcba_usb 1-1:0.95 can0: device disconnected
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3377/0x3eb0
kernel/locking/lockdep.c:3828
Read of size 8 at addr ffff8881d2e98f48 by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0+ #0
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+0xca/0x13e lib/dump_stack.c:113
print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
kasan_report+0xe/0x12 mm/kasan/common.c:634
__lock_acquire+0x3377/0x3eb0 kernel/locking/lockdep.c:3828
lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4487
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
_raw_spin_lock_irq+0x2d/0x40 kernel/locking/spinlock.c:167
spin_lock_irq include/linux/spinlock.h:363 [inline]
usb_kill_anchored_urbs+0x1e/0x110 drivers/usb/core/urb.c:787
mcba_urb_unlink drivers/net/can/usb/mcba_usb.c:711 [inline]
mcba_usb_disconnect+0xd6/0xe4 drivers/net/can/usb/mcba_usb.c:881
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x420/0xb10 drivers/base/core.c:2375
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the page:
page:ffffea00074ba600 refcount:0 mapcount:-128 mapping:0000000000000000
index:0x0
flags: 0x200000000000000()
raw: 0200000000000000 ffffea0007479208 ffff88821fffac18 0000000000000000
raw: 0000000000000000 0000000000000003 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881d2e98e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8881d2e98e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ffff8881d2e98f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff8881d2e98f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8881d2e99000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
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[Johan Hovold]

Fix posted

https://lkml.kernel.org/r/2019100110291...@kernel.org

Johan