Re: [PATCH 1/1] pstore/ram: Ensure stable pmsg address with per-CPU ftrace buffers

From: Kees Cook
Date: Tue Oct 11 2022 - 16:04:19 EST


On Tue, Oct 11, 2022 at 12:59:50PM -0700, Paramjit Oberoi wrote:
> > Hm, interesting point. Since only ftrace is dynamically sized in this
> > fashion, how about just moving the pmsg allocation before ftrace, and
> > adding a comment that for now ftrace should be allocated last?
>
> That is a good idea, and it would solve the problem.
>
> The only downside is it would break some code that works today because it
> ran in contexts where the pmsg address was stable (no per-cpu ftrace
> buffers, or power-of-two CPUs).

I don't follow? And actually, I wonder about the original patch now --
nothing should care about the actual addresses. Everything should be
coming out of the pstore filesystem.

--
Kees Cook