Re: [PATCH] HID: playstation: Fix DualShock4 dongle hotplug work use-after-free

[Fan Wu]

Please drop this patch.

__hid_input_report() returns -EBUSY when it cannot take
hdev->driver_input_lock, and hid_device_probe() and hid_device_remove()
hold that lock across the driver's ->probe() and ->remove() callbacks.
hid-playstation never calls hid_device_io_start(), so input reports
cannot reach dualshock4_dongle_parse_report() while
dualshock4_create() or dualshock4_remove() run. The window this patch
tried to guard does not exist, and the cancel_work_sync() calls that
were already there are sufficient.

The issue came from our static analysis tooling, which missed that
the HID core serializes the report path against probe and remove.

Sorry for the noise.

Fan Wu