From: Steve Capper <Steve.Capper@arm.com>
To: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Qian Cai <cai@lca.pw>, Andrey Konovalov <andreyknvl@google.com>,
nd <nd@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: "arm64/for-next/core" causes boot panic
Date: Tue, 13 Aug 2019 14:41:32 +0000 [thread overview]
Message-ID: <20190813144130.GA15482@capper-ampere.manchester.arm.com> (raw)
In-Reply-To: <20190813140451.GA24579@capper-ampere.manchester.arm.com>
On Tue, Aug 13, 2019 at 03:04:52PM +0100, Steve Capper wrote:
> Hi Will,
>
> On Tue, Aug 13, 2019 at 01:06:44PM +0100, Will Deacon wrote:
> > [+Steve]
> >
> > On Tue, Aug 13, 2019 at 11:58:52AM +0100, Will Deacon wrote:
> > > On Tue, Aug 13, 2019 at 10:02:01AM +0100, Will Deacon wrote:
> > > > On Mon, Aug 12, 2019 at 05:51:35PM -0400, Qian Cai wrote:
> > > > > Booting today's linux-next on an arm64 server triggers a panic with
> > > > > CONFIG_KASAN_SW_TAGS=y pointing to this line,
> > > >
> > > > Is this the only change on top of defconfig? If not, please can you share
> > > > your full .config?
> > > >
> > > > > kfree()->virt_to_head_page()->compound_head()
> > > > >
> > > > > unsigned long head = READ_ONCE(page->compound_head);
> > > > >
> > > > > The bisect so far indicates one of those could be bad,
> > > >
> > > > I guess that means the issue is reproducible on the arm64 for-next/core
> > > > branch. Once I have your .config, I'll give it a go.
> > >
> > > FWIW, I've managed to reproduce this using defconfig + SW_TAGS on
> > > for-next/core, so I'll keep investigating.
>
> I've installed clang-8 and enabled CONFIG_KASAN_SW_TAGS and was able to
> reproduce the problem quite rapidly. Many apologies for missing this
> before in my testing.
>
> >
> > Right, hacky diff below seems to resolve this, so I'll split this up into
> > some proper patches as there is more than one bug here.
> >
> > Thanks,
> >
> > Will
> >
> > --->8
> >
> > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> FWIW, this fixed the crashes I experienced, I'll run some additional
> tests.
>
This works for me with 52-bit VAs + CONFIG_KASAN_SW_TAGS +
CONFIG_DEBUG_VIRTUAL + CONFIG_DEBUG_VM
FWIW:
Tested-by: Steve Capper <steve.capper@arm.com>
Cheers,
--
Steve
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prev parent reply other threads:[~2019-08-13 14:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 21:51 "arm64/for-next/core" causes boot panic Qian Cai
2019-08-13 9:02 ` Will Deacon
2019-08-13 10:58 ` Will Deacon
2019-08-13 12:06 ` Will Deacon
2019-08-13 14:04 ` Steve Capper
2019-08-13 14:41 ` Steve Capper [this message]
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