Re: [PATCH v1 0/2] spi: Make dummy SG handling robust

From: Andy Shevchenko
Date: Fri May 31 2024 - 17:46:25 EST


On Fri, May 31, 2024 at 8:14 PM Nícolas F. R. A. Prado
<nfraprado@xxxxxxxxxxxxx> wrote:
>
> On Fri, May 31, 2024 at 06:51:46PM +0300, Andy Shevchenko wrote:
> > On Fri, May 31, 2024 at 6:46 PM Andy Shevchenko
> > <andy.shevchenko@xxxxxxxxx> wrote:
> > > On Fri, May 31, 2024 at 5:37 PM Nícolas F. R. A. Prado
> > > <nfraprado@xxxxxxxxxxxxx> wrote:
> > > > On Fri, May 31, 2024 at 12:44:31PM +0300, Andy Shevchenko wrote:

...

> > > > applying either of these patches causes issues. See the traces for each one
> > > > below. This was tested on top of next-20240531, which works fine.
> > >
> > > Oh, thank you very much for prompt testing! Can you test just the
> > > second one without the revert?
> >
> > Ah, you wrote "either", so it seems you have tried that already.
>
> Yes exactly. Both patches are troublesome. Patch 2 causes a slightly different
> null pointer dereference, in "dcache_clean_poc+0x20/0x38", as the stack trace I
> posted shows.

I have sent a new series where the last patch has a massive rework of
the cur_msg_mapped flag. Would be nice to see if it passes your tests.
The main idea there is to actually move to per transfer flag(s) from
per message one.

--
With Best Regards,
Andy Shevchenko