em28xx 1-1:0.71: Config register raw data: 0xfffffffb
em28xx 1-1:0.71: AC97 chip type couldn't be determined
em28xx 1-1:0.71: No AC97 audio processor
==================================================================
BUG: KASAN: use-after-free in __list_add_valid+0x93/0xa0 lib/list_debug.c:26
Read of size 8 at addr ffff8881c3ef4250 by task kworker/1:5/3184

CPU: 1 PID: 3184 Comm: kworker/1:5 Not tainted 5.9.0-rc1-syzkaller #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+0xf6/0x16e lib/dump_stack.c:118
 print_address_description.constprop.0+0x1c/0x210 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x37/0x7c mm/kasan/report.c:530
 __list_add_valid+0x93/0xa0 lib/list_debug.c:26
 __list_add include/linux/list.h:67 [inline]
 list_add_tail include/linux/list.h:100 [inline]
 em28xx_init_extension+0x44/0x1f0 drivers/media/usb/em28xx/em28xx-core.c:1125
 em28xx_init_dev.constprop.0+0xa80/0x15cb drivers/media/usb/em28xx/em28xx-cards.c:3558
 em28xx_usb_probe.cold+0xcb6/0x252f drivers/media/usb/em28xx/em28xx-cards.c:3907
 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:374
 really_probe+0x291/0xde0 drivers/base/dd.c:553
 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738
 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844
 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
 __device_attach+0x228/0x4a0 drivers/base/dd.c:912
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
 device_add+0xb51/0x1c70 drivers/base/core.c:2930
 usb_set_configuration+0xf05/0x18a0 drivers/usb/core/message.c:2032
 usb_generic_driver_probe+0xba/0xf2 drivers/usb/core/generic.c:239
 usb_probe_device+0xd9/0x250 drivers/usb/core/driver.c:272
 really_probe+0x291/0xde0 drivers/base/dd.c:553
 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:738
 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:844
 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
 __device_attach+0x228/0x4a0 drivers/base/dd.c:912
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
 device_add+0xb51/0x1c70 drivers/base/core.c:2930
 usb_new_device.cold+0x71d/0xfd4 drivers/usb/core/hub.c:2554
 hub_port_connect drivers/usb/core/hub.c:5208 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5348 [inline]
 port_event drivers/usb/core/hub.c:5494 [inline]
 hub_event+0x2361/0x4390 drivers/usb/core/hub.c:5576
 process_one_work+0x94c/0x15f0 kernel/workqueue.c:2269
 process_scheduled_works kernel/workqueue.c:2331 [inline]
 worker_thread+0x82b/0x1120 kernel/workqueue.c:2417
 kthread+0x392/0x470 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the page:
page:00000000566f309f refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1c3ef4
flags: 0x200000000000000()
raw: 0200000000000000 ffffea000751e708 ffff88821fffabd0 0000000000000000
raw: 0000000000000000 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881c3ef4100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c3ef4180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881c3ef4200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                 ^
 ffff8881c3ef4280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c3ef4300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================