CVE-2021-47479

In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8712: fix use-after-free in rtl8712_dl_fw Syzbot reported
use-after-free in rtl8712_dl_fw(). The problem was in race condition
between r871xu_dev_remove() ->ndo_open() callback. It’s easy to see from
crash log, that driver accesses released firmware in ->ndo_open() callback.
It may happen, since driver was releasing firmware before unregistering
netdev. Fix it by moving unregister_netdev() before cleaning up resources.
Call Trace: … rtl871x_open_fw drivers/staging/rtl8712/hal_init.c:83
[inline] rtl8712_dl_fw+0xd95/0xe10 drivers/staging/rtl8712/hal_init.c:170
rtl8712_hal_init drivers/staging/rtl8712/hal_init.c:330 [inline]
rtl871x_hal_init+0xae/0x180 drivers/staging/rtl8712/hal_init.c:394
netdev_open+0xe6/0x6c0 drivers/staging/rtl8712/os_intfs.c:380
__dev_open+0x2bc/0x4d0 net/core/dev.c:1484 Freed by task 1306: …
release_firmware+0x1b/0x30 drivers/base/firmware_loader/main.c:1053
r871xu_dev_remove+0xcc/0x2c0 drivers/staging/rtl8712/usb_intf.c:599
usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458