linux-kernel - Re: [PATCH v1 00/17] tee: Use bus callbacks instead of driver callbacks

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Message-ID: <aUJxiioKnDVSC34H@sumit-xelite>
Date: Wed, 17 Dec 2025 14:32:02 +0530
From: Sumit Garg <sumit.garg@...nel.org>
To: Uwe Kleine-König <u.kleine-koenig@...libre.com>
Cc: Sumit Garg <sumit.garg@....qualcomm.com>,
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	Jason Gunthorpe <jgg@...pe.ca>
Subject: Re: [PATCH v1 00/17] tee: Use bus callbacks instead of driver
 callbacks

On Wed, Dec 17, 2025 at 09:21:41AM +0100, Uwe Kleine-König wrote:
> Hello Sumit,
> 
> On Wed, Dec 17, 2025 at 01:25:39PM +0530, Sumit Garg wrote:
> > On Tue, Dec 16, 2025 at 12:08:38PM +0100, Uwe Kleine-König wrote:
> > > On Tue, Dec 16, 2025 at 01:08:38PM +0530, Sumit Garg wrote:
> > > > On Mon, Dec 15, 2025 at 3:02 PM Uwe Kleine-König
> > > > <u.kleine-koenig@...libre.com> wrote:
> > > > >  - Why does optee_probe() in drivers/tee/optee/smc_abi.c unregister all
> > > > >    optee devices in its error path (optee_unregister_devices())?
> > > > 
> > > > This is mostly to take care of if any device got registered before the
> > > > failure occured. Let me know if you have a better way to address that.
> > > 
> > > Without understanding the tee stuff, I'd say: Don't bother and only undo
> > > the things that probe did before the failure.
> > 
> > True, but this is special case where if there is any leftover device
> > registered from the TEE implementation then it is likely going to cause
> > the corresponding kernel client driver crash.
> 
> You are aware that this is racy? So if a driver crashes e.g. after
> teedev_close_context() it might happen that it is registered just after
> optee_unregister_devices() returns.
> 

I see your point about the unavoidable race. Maybe it's better to not
try anything and let the kernel client driver fail.

-Sumit