Re: [PATCH AUTOSEL 5.19 54/64] ARM: 9202/1: kasan: support CONFIG_KASAN_VMALLOC

[Sasha Levin]

On Tue, Aug 16, 2022 at 04:45:14PM +0200, Ard Biesheuvel wrote:
> On Sun, 14 Aug 2022 at 17:30, Sasha Levin <sashal@xxxxxxxxxx> wrote:
> > From: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
> >
> > [ Upstream commit 565cbaad83d83e288927b96565211109bc984007 ]
> >
> > Simply make shadow of vmalloc area mapped on demand.
> >
> > Since the virtual address of vmalloc for Arm is also between
> > MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
> > address has already included between KASAN_SHADOW_START and
> > KASAN_SHADOW_END.
> > Thus we need to change nothing for memory map of Arm.
> >
> > This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
> > and support CONFIG_VMAP_STACK with KASan.
> >
> > Signed-off-by: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
> > Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> This patch does not belong in -stable. It has no fixes: or cc:stable
> tags, and the contents are completely inappropriate for backporting
> anywhere. In general, I think that no patch that touches arch/arm
> (with the exception of DTS updates, perhaps) should ever be backported
> unless proposed or acked by the maintainer.

I'll drop it.

> I know I shouldn't ask, but how were these patches build/boot tested?
> KAsan is very tricky to get right, especially on 32-bit ARM ...

They were only build tested at this stage. They go through
boot/functional test only after they are actually queued up for the
various trees.

--
Thanks,
Sasha