Re: [PATCH 2/2] USB: usbip: drop redundant device reference

From: Shuah Khan

Date: Tue Mar 10 2026 - 17:51:54 EST


On 3/10/26 02:35, Johan Hovold wrote:
On Mon, Mar 09, 2026 at 02:26:03PM -0600, Shuah Khan wrote:
On 3/5/26 06:38, Johan Hovold wrote:
Driver core holds a reference to the USB device while it is bound to a
driver and there is no need to take additional references unless the
structure is needed after disconnect.

In this case it is necessary for stub driver to hang on to the reference
to maintain exported device status.

But the driver does not hold on to the reference taken at probe after
disconnect returns. The stub device itself is even freed at disconnect
and cannot be used to release the reference.

Which exported device status are you referring to here?

I am referring to the device status that usbip host exports to
the client side. The interaction between host and client is
handled from stub rx, tx, and also event handler.

Having the reference to the device helps so the device sticks
around until the stub driver no longer needs it so we don't see
use after free type issues.

thanks,
-- Shuah