Re: [GIT PULL] TEE shared memory fix for 7.0

[Marco Felsch]

On 26-03-17, Jens Wiklander wrote:
> Hi,
> 
> On Tue, Mar 17, 2026 at 9:51 AM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> >
> > On Mon, Mar 16, 2026 at 08:41:50AM +0100, Jens Wiklander wrote:
> > > Hello arm-soc maintainers,
> > >
> > > Please pull this patch removing the refcounting of kernel pages within
> > > the TEE shared memory helper.
> > >
> > > Thanks,
> > > Jens
> > >
> > > The following changes since commit 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f:
> > >
> > >   Linux 7.0-rc1 (2026-02-22 13:18:59 -0800)
> > >
> > > are available in the Git repository at:
> > >
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/jenswi/linux-tee.git tags/tee-fix-for-v7.0
> > >
> > > for you to fetch changes up to 08d9a4580f71120be3c5b221af32dca00a48ceb0:
> > >
> > >   tee: shm: Remove refcounting of kernel pages (2026-03-03 09:03:04 +0100)
> > >
> > > ----------------------------------------------------------------
> > > TEE shared memory update for 7.0
> > >
> > > Remove refcounting of kernel pages in register_shm_helper() to support
> > > slab allocations.
> >
> > That's a supposed fix for a year old commit, not current RC, and the
> > commit msg does not explain what is the bug being fixed here. Looks like
> > it is doing improvement, not a fix. Can you provide here more
> > explanation of the actual bug being fixed to justify this going to
> > current RC fixes?
> 
> I'm under the impression that it is a fix rather than an improvement.
> However, since it has been stewing for a while, it's clearly not
> urgent. I don't have anything specific on the bug fix, other than that
> we're supposed to stop taking those refcounts. Perhaps Sumit, Marco,
> or Matthew can add something?

It's a long outstanding fix regarding memory page management. The
userspace gets informed about this memory API misuse via a warning print
incl. a backtrace. This gets triggered only if userspace uses OP-TEE
trusted-keys or the OP-TEE EFI variables. Therefore I would like to get
it into 7.0 but 7.1 fine too.

Regards,
  Marco

> 
> Cheers,
> Jens
> 

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