Re: [PATCH 1/2] pinctrl: tegra: Duplicate pinmux functions table

[Thierry Reding <thierry.reding@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 1582 bytes --]

On Thu, Jun 01, 2023 at 01:19:45PM +0200, Linus Walleij wrote:
> On Tue, May 30, 2023 at 12:53 PM Thierry Reding
> <thierry.reding@gmail.com> wrote:
> 
> > From: Thierry Reding <treding@nvidia.com>
> >
> > The function table is filled with group information based on other
> > instance-specific data at runtime. However, the function table can be
> > shared between multiple instances, causing the ->probe() function for
> > one instance to overwrite the table of a previously probed instance.
> >
> > Fix this by sharing only the function names and allocating a separate
> > function table for each instance.
> >
> > Fixes: 5a0047360743 ("pinctrl: tegra: Separate Tegra194 instances")
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> 
> Both patches applied!
> 
> I can't figure out if the problem is urgent or just wasting memory, so
> I applied it as non-urgent fix for now, tell me if this needs to go
> upstream pronto.

I think you might be able to write a device tree that triggers this, but
so far I've only seen it cause an WARN splat when accessing the debugfs
attribute that reads out the pinmux functions. I think Prathamesh had
mentioned it could also hang the system when you access debugfs.

Overall I don't think this is very urgent. We only observed this as part
of testing the Tegra234 patches that are under review, so it's probably
uncommon for people to run the problematic code paths.

No matter what you decide, the Fixes: tag should make sure it goes into
stable releases which is probably good enough.

Thierry

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]