Re: [PATCH] mm,ima,kexec: use memblock_free_late from ima_free_kexec_buffer

[Rob Herring]

On Fri, Jul 21, 2023 at 08:40:41PM -0400, Rik van Riel wrote:
> On Fri, 2023-07-21 at 13:38 -0600, Rob Herring wrote:
> > On Thu, Jul 20, 2023 at 10:14:31AM -0400, Rik van Riel wrote:
> > > The code calling ima_free_kexec_buffer runs long after the memblock
> > > allocator has already been torn down, potentially resulting in a
> > > use
> > > after free in memblock_isolate_range.
> > > 
> > > With KASAN or KFENCE, this use after free will result in a BUG
> > > from the idle task, and a subsequent kernel panic.
> > > 
> > > Switch ima_free_kexec_buffer over to memblock_free_late to avoid
> > > that issue.
> > > 
> > > Fixes: fee3ff99bc67 ("powerpc: Move arch independent ima kexec
> > > functions to drivers/of/kexec.c")
> > 
> > Fixes: b69a2afd5afc ("x86/kexec: Carry forward IMA measurement log on
> > kexec")
> > 
> Thank you for digging further back in the history of that code.
> 
> > Acked-by: Rob Herring <robh@xxxxxxxxxx>
> > 
> > (I'm assuming someone else is taking this)
> 
> I hope so, but I don't know who...

You could split this into 2 patches, then there's no doubt. And each 
Fixes is clear.

Rob