Re: [PATCH] x86: Fix build of UML with KASAN

From: Vincent Whitchurch <Vincent.Whitchurch@axis.com>
To: Vincent Whitchurch <Vincent.Whitchurch@axis.com>,
	"davidgow@google.com" <davidgow@google.com>,
	"x86@kernel.org" <x86@kernel.org>
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	kernel <kernel@axis.com>,
	"rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
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Subject: Re: [PATCH] x86: Fix build of UML with KASAN
Date: Mon, 11 Sep 2023 07:26:00 +0000	[thread overview]
Message-ID: <f11475f922994b88f5adb14d23240716e16d5303.camel@axis.com> (raw)
In-Reply-To: <CABVgOS=X1=NC9ad+WV4spFFh4MBHLodhcyQ=Ks=6-FpXrbRTdA@mail.gmail.com>

On Sat, 2023-06-10 at 16:34 +0800, David Gow wrote:
> On Fri, 9 Jun 2023 at 19:19, Vincent Whitchurch
> <vincent.whitchurch@axis.com> wrote:
> > 
> > Building UML with KASAN fails since commit 69d4c0d32186 ("entry, kasan,
> > x86: Disallow overriding mem*() functions") with the following errors:
> > 
> >  $ tools/testing/kunit/kunit.py run --kconfig_add CONFIG_KASAN=y
> >  ...
> >  ld: mm/kasan/shadow.o: in function `memset':
> >  shadow.c:(.text+0x40): multiple definition of `memset';
> >  arch/x86/lib/memset_64.o:(.noinstr.text+0x0): first defined here
> >  ld: mm/kasan/shadow.o: in function `memmove':
> >  shadow.c:(.text+0x90): multiple definition of `memmove';
> >  arch/x86/lib/memmove_64.o:(.noinstr.text+0x0): first defined here
> >  ld: mm/kasan/shadow.o: in function `memcpy':
> >  shadow.c:(.text+0x110): multiple definition of `memcpy';
> >  arch/x86/lib/memcpy_64.o:(.noinstr.text+0x0): first defined here
> > 
> > If I'm reading that commit right, the !GENERIC_ENTRY case is still
> > supposed to be allowed to override the mem*() functions, so use weak
> > aliases in that case.
> > 
> > Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions")
> > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
> > ---
> 
> Thanks: I stumbled into this the other day and ran out of time to debug it.
> 
> I've tested that it works here.
> 
> Tested-by: David Gow <davidgow@google.com>

Thanks.  Perhaps someone could pick this up?  It's been a few months,
and the build problem is still present on v6.6-rc1.
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