Re: [PATCH 2/5 v16] ARM: Replace string mem* functions for KASan - Russell King

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Ahmad Fatoum <a.fatoum@pengutronix.de>,
	Arnd Bergmann <arnd@arndb.de>,
	Abbott Liu <liuwenliang@huawei.com>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Linux-Next Mailing List <linux-next@vger.kernel.org>,
	Alexander Potapenko <glider@google.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH 2/5 v16] ARM: Replace string mem* functions for KASan
Date: Fri, 6 Nov 2020 15:15:54 +0000	[thread overview]
Message-ID: <20201106151554.GU1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CACRpkdaBnLsQB-b8fYaXGV=_i2y7pyEaVX=8pCAdjPEVHtqV4Q@mail.gmail.com>

On Fri, Nov 06, 2020 at 02:37:21PM +0100, Linus Walleij wrote:
> On Fri, Nov 6, 2020 at 10:44 AM Nathan Chancellor
> <natechancellor@gmail.com> wrote:
> > On Fri, Nov 06, 2020 at 09:28:09AM +0100, Ard Biesheuvel wrote:
> 
> > > AFAIK there is an incompatible change in -next to change the
> > > definition of the __alias() macro
> >
> > Indeed. The following diff needs to be applied as a fixup to
> > treewide-remove-stringification-from-__alias-macro-definition.patch in
> > mmotm.
> >
> > Cheers,
> > Nathan
> >
> > diff --git a/arch/arm/boot/compressed/string.c b/arch/arm/boot/compressed/string.c
> > index 8c0fa276d994..cc6198f8a348 100644
> > --- a/arch/arm/boot/compressed/string.c
> > +++ b/arch/arm/boot/compressed/string.c
> > @@ -21,9 +21,9 @@
> >  #undef memcpy
> >  #undef memmove
> >  #undef memset
> > -void *__memcpy(void *__dest, __const void *__src, size_t __n) __alias(memcpy);
> > -void *__memmove(void *__dest, __const void *__src, size_t count) __alias(memmove);
> > -void *__memset(void *s, int c, size_t count) __alias(memset);
> > +void *__memcpy(void *__dest, __const void *__src, size_t __n) __alias("memcpy");
> > +void *__memmove(void *__dest, __const void *__src, size_t count) __alias("memmove");
> > +void *__memset(void *s, int c, size_t count) __alias("memset");
> >  #endif
> >
> >  void *memcpy(void *__dest, __const void *__src, size_t __n)
> 
> Aha. So shall we submit this to Russell? I figure that his git will not
> build *without* the changes from mmotm?
> 
> That tree isn't using git either is it?
> 
> Is this one of those cases where we should ask Stephen R
> to carry this patch on top of -next until the merge window?

Another solution would be to drop 9017/2 ("Enable KASan for ARM")
until the following merge window, and queue up the non-conflicing
ARM KASan fixes in my "misc" branch along with the rest of KASan,
and the conflicting patches along with 9017/2 in the following
merge window.

That means delaying KASan enablement another three months or so,
but should result in less headaches about how to avoid build
breakage with different bits going through different trees.

Comments?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

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