usb: gadget: f_ncm: Refactor bind path to use __free()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_ncm: Refactor bind path to use __free() After an bind/unbind cycle, the ncm->notify_req is left stale. If a subsequent bind fails, the unified error label attempts to free this stale request, leading to a NULL pointer dereference when accessing ep->ops->free_request. Refactor the error handling in the bind path to use the __free() automatic cleanup mechanism. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 Call trace: usb_ep_free_request+0x2c/0xec ncm_bind+0x39c/0x3dc usb_add_function+0xcc/0x1f0 configfs_composite_bind+0x468/0x588 gadget_bind_driver+0x104/0x270 really_probe+0x190/0x374 __driver_probe_device+0xa0/0x12c driver_probe_device+0x3c/0x218 __device_attach_driver+0x14c/0x188 bus_for_each_drv+0x10c/0x168 __device_attach+0xfc/0x198 device_initial_probe+0x14/0x24 bus_probe_device+0x94/0x11c device_add+0x268/0x48c usb_add_gadget+0x198/0x28c dwc3_gadget_init+0x700/0x858 __dwc3_set_mode+0x3cc/0x664 process_scheduled_works+0x1d8/0x488 worker_thread+0x244/0x334 kthread+0x114/0x1bc ret_from_fork+0x10/0x20

References

• https://git.kernel.org/stable/c/185193a4714aa9c78437a7a1858fbe5771f0f45c
• https://git.kernel.org/stable/c/f37de8dec6a4c379b4b8486003a1de00ff8cff3b
• https://git.kernel.org/stable/c/1cde4516295a030cb8ab4c93114ca3b6c3c6a1e2
• https://git.kernel.org/stable/c/d3fe7143928d8dfa2ec7bac9f906b48bc75b98ee
• https://git.kernel.org/stable/c/ed78f4d6079d872432b1ed54f155ef61965d3137
• https://git.kernel.org/stable/c/75a5b8d4ddd4eb6b16cb0b475d14ff4ae64295ef