[PATCH v2 1/1] mm: kfence: apply kmemleak_ignore_phys on early allocated pool

[Marco Elver]

On Sat, 16 Jul 2022 at 20:43, Geert Uytterhoeven <geert at linux-m68k.org> wrote:
[...]
> > - This patch has been accused of crashing the kernel:
> >
> >         https://lkml.kernel.org/r/YsFeUHkrFTQ7T51Q@xsang-OptiPlex-9020
> >
> >   Do we think that report is bogus?
>
> I think all of this is highly architecture-specific...

The report can be reproduced on i386 with CONFIG_X86_PAE=y. But e.g.
mm/memblock.c:memblock_free() is also guilty of using __pa() on
previously memblock_alloc()'d addresses. Looking at the phys addr
before memblock_alloc() does virt_to_phys(), the result of __pa()
looks correct even on PAE, at least for the purpose of passing it on
to kmemleak(). So I don't know what that BUG_ON(slow_virt_to_phys() !=
phys_addr) is supposed to tell us here.

Ideas?