Re: [PATCH 05/17] USB: Lock registered interfaces during manual driver binding

[Leon Romanovsky]

On Thu, Nov 05, 2026 at 03:04:18PM -0500, Alan Stern wrote:
> On Thu, Nov 05, 2026 at 08:44:42PM +0200, Leon Romanovsky wrote:
> > On Thu, Nov 05, 2026 at 12:24:33PM -0500, Alan Stern wrote:
> > > On Thu, Nov 05, 2026 at 01:42:18PM +0200, Leon Romanovsky wrote:
> > > > From: Leon Romanovsky <leonro@xxxxxxxxxx>
> > > > 
> > > > Interface claims hold the USB device lock, but device_bind_driver()
> > > > requires the target interface lock. Without it, trust-policy writes can
> > > > race admission.
> > > 
> > > This says nothing about usb_driver_release_refused_claim() and the code 
> > > related to it.  It is an incomplete description of the patch.
> > > 
> > > Note that nothing prevents drivers from using an interface they claim 
> > > before that interface is registered.  For your scheme to work properly, 
> > > you should make sure the claim is authorized when 
> > > usb_driver_claim_interface() is called, not when the interface is 
> > > registered.
> > 
> > This patch is unrelated to authorization;
> 
> I meant "authorization" in its generic sense.  When you don't trust 
> something, you don't authorize it to do anything.  Pretend I had written 
> "the interface being claimed is trusted" in place of "the claim is 
> authorized" above.

I will combine existing USB authorization scheme with device trust in v2.

> 
> >  it ensures that the lock is
> > acquired when the driver is bound.
> 
> That may have been your intention when the patch was created, but if you 
> read the patch you'll see that it includes a whole bunch of material 
> not related to locking during binding.  Namely, this part:

Once I added `device_lock()` to `bind`, I had to add it to `unbind` as well.

Thanks