Re: [PATCH v8 2/2] usb: gadget: udc: core: Prevent soft_connect_store() race

[Alan Stern]

On Fri, Jun 09, 2023 at 01:02:27AM +0000, Badhri Jagan Sridharan wrote:
> usb_udc_connect_control(), soft_connect_store() and
> usb_gadget_deactivate() can potentially race against each other to invoke
> usb_gadget_connect()/usb_gadget_disconnect(). To prevent this, guard
> udc->started, gadget->allow_connect, gadget->deactivate and
> gadget->connect with connect_lock so that ->pullup() is only invoked when
> the gadget is bound, started and not deactivated. The routines
> usb_gadget_connect_locked(), usb_gadget_disconnect_locked(),
> usb_udc_connect_control_locked(), usb_gadget_udc_start_locked(),
> usb_gadget_udc_stop_locked() are called with this lock held.
> 
> An earlier version of this commit was reverted due to the crash reported in
> https://lore.kernel.org/all/ZF4BvgsOyoKxdPFF@xxxxxxxxxxxxxxxxxxxxxxxxxxxx/.
> commit 16737e78d190 ("usb: gadget: udc: core: Offload usb_udc_vbus_handler processing")
> addresses the crash reported.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 628ef0d273a6 ("usb: udc: add usb_udc_vbus_handler")
> Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
> ---

Reviewed-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>