Bug report: kernel paniced when system hibernates

[Alexandre Ghiti]

Hi everyone,

On Thu, May 25, 2023 at 11:24 PM Conor Dooley <conor at kernel.org> wrote:
>
> On Thu, May 25, 2023 at 01:06:04PM -0700, Atish Patra wrote:
> > On Thu, May 25, 2023 at 11:39 AM Conor Dooley <conor at kernel.org> wrote:
> > >
> > > On Thu, May 25, 2023 at 11:37:40AM -0700, Atish Patra wrote:
> > >
> > > > Any testing of hibernation still needs to revert the patch until we
> > > > have the proper fix.
> > >
> > > "the patch" is what exactly? I assume you don't mean depending on
> > > NONPORTABLE, since that is a Kconfig option.
> >
> > Nope. Sorry I meant the commit
> >
> > 3335068 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
>
> Ah, if your SBI implementation is one of the affected ones, yeah.
> If not, you can just set NONPORTABLE :)

@Björn Töpel emitted the idea of excluding from the hibernation all
the memory nodes in the "/reserved-memory" node
(https://elixir.bootlin.com/linux/v6.4-rc1/source/Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml):
I have to admit that I don't see why it is not done by default by the
kernel.

Unless there is stuff in this node that needs to be "hibernated", I
think that would be a very good solution since we would not rely on
the name of the "internal" nodes of "/reserved-memory" (i.e.
"mmode_resv").

I'm digging into why it is not done by default, just wanted to have
your feedback before the week-end :)