USB: gadget: Fix use-after-free during usb config switch

In the Linux kernel, the following vulnerability has been resolved:

USB: gadget: Fix use-after-free during usb config switch

In the process of switching USB config from rndis to other config,

if the hardware does not support the ->pullup callback, or the

hardware encounters a low probability fault, both of them may cause

the ->pullup callback to fail, which will then cause a system panic

(use after free).

The gadget drivers sometimes need to be unloaded regardless of the

hardware's behavior.

Analysis as follows:

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(1) write /config/usb_gadget/g1/UDC "none"

gether_disconnect+0x2c/0x1f8

rndis_disable+0x4c/0x74

composite_disconnect+0x74/0xb0

configfs_composite_disconnect+0x60/0x7c

usb_gadget_disconnect+0x70/0x124

usb_gadget_unregister_driver+0xc8/0x1d8

gadget_dev_desc_UDC_store+0xec/0x1e4

(2) rm /config/usb_gadget/g1/configs/b.1/f1

rndis_deregister+0x28/0x54

rndis_free+0x44/0x7c

usb_put_function+0x14/0x1c

config_usb_cfg_unlink+0xc4/0xe0

configfs_unlink+0x124/0x1c8

vfs_unlink+0x114/0x1dc

(3) rmdir /config/usb_gadget/g1/functions/rndis.gs4

panic+0x1fc/0x3d0

do_page_fault+0xa8/0x46c

do_mem_abort+0x3c/0xac

el1_sync_handler+0x40/0x78

0xffffff801138f880

rndis_close+0x28/0x34

eth_stop+0x74/0x110

dev_close_many+0x48/0x194

rollback_registered_many+0x118/0x814

unregister_netdev+0x20/0x30

gether_cleanup+0x1c/0x38

rndis_attr_release+0xc/0x14

kref_put+0x74/0xb8

configfs_rmdir+0x314/0x374

If gadget->ops->pullup() return an error, function rndis_close() will be

called, then it will causes a use-after-free problem.

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