[PATCH v2 1/2] ARM: ioremap: Sync PGDs for VMALLOC shadow

[Linus Walleij]

On Wed, Oct 16, 2024 at 9:15 PM Linus Walleij <linus.walleij at linaro.org> wrote:

> When sync:ing the VMALLOC area to other CPUs, make sure to also
> sync the KASAN shadow memory for the VMALLOC area, so that we
> don't get stale entries for the shadow memory in the top level PGD.
>
> Since we are now copying PGDs in two instances, create a helper
> function named memcpy_pgd() to do the actual copying, and
> create a helper to map the addresses of VMALLOC_START and
> VMALLOC_END into the corresponding shadow memory.
>
> Cc: stable at vger.kernel.org
> Fixes: 565cbaad83d8 ("ARM: 9202/1: kasan: support CONFIG_KASAN_VMALLOC")
> Link: https://lore.kernel.org/linux-arm-kernel/a1a1d062-f3a2-4d05-9836-3b098de9db6d@foss.st.com/
> Reported-by: Clement LE GOFFIC <clement.legoffic at foss.st.com>
> Suggested-by: Mark Rutland <mark.rutland at arm.com>
> Suggested-by: Russell King (Oracle) <linux at armlinux.org.uk>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>

As it turns out in my confusion I have missed that the more or less identical
patch with a different subject (talking about recursion) is already submitted
by Melon Liu and waiting in the patch tracker:
https://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=9427/1

I've tested it and it solves the problem equally well.

I even reviewed that and didn't remember it...

I will submit patch 2/2 into the patch tracker and let Melon's
patch deal with this issue.

Yours,
Linus Walleij