From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: Bad page state splats on arm64, v4.11-rc{3,4}
Date: Mon, 3 Apr 2017 11:56:29 +0100 [thread overview]
Message-ID: <20170403105629.GB18905@leverpostej> (raw)
In-Reply-To: <20170331175845.GE6488@leverpostej>
On Fri, Mar 31, 2017 at 06:58:45PM +0100, Mark Rutland wrote:
> Hi,
>
> I'm seeing intermittent bad page state splats on arm64 with 4.11-rc3 and
> v4.11-rc4. I have not tested earlier kernels, or other architectures.
>
> So far, it looks like the flags are always bad in the same
> way:
>
> bad because of flags: 0x80(waiters)
>
> ... though I don't know if that's definitely the case for splat 4, the
> BUG at mm/page_alloc.c:800.
>
> I see this in QEMU VMs launched by Syzkaller, triggering once every few
> hours. So far, I have not been able to reproduce the issue in any other
> way (including using syz-repro).
It looks like this may be an issue with the arm64 HUGETLB code.
I wasn't able to trigger the issue over the weekend on a kernel with
HUGETLBFS disabled. There are known issues with our handling of
contiguous entries, and this might be an artefact of that.
I'll see if I can narrow this down any further.
Thanks,
Mark.
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com>
To: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
will.deacon@arm.com, catalin.marinas@arm.com,
punit.agrawal@arm.com
Subject: Re: Bad page state splats on arm64, v4.11-rc{3,4}
Date: Mon, 3 Apr 2017 11:56:29 +0100 [thread overview]
Message-ID: <20170403105629.GB18905@leverpostej> (raw)
In-Reply-To: <20170331175845.GE6488@leverpostej>
On Fri, Mar 31, 2017 at 06:58:45PM +0100, Mark Rutland wrote:
> Hi,
>
> I'm seeing intermittent bad page state splats on arm64 with 4.11-rc3 and
> v4.11-rc4. I have not tested earlier kernels, or other architectures.
>
> So far, it looks like the flags are always bad in the same
> way:
>
> bad because of flags: 0x80(waiters)
>
> ... though I don't know if that's definitely the case for splat 4, the
> BUG at mm/page_alloc.c:800.
>
> I see this in QEMU VMs launched by Syzkaller, triggering once every few
> hours. So far, I have not been able to reproduce the issue in any other
> way (including using syz-repro).
It looks like this may be an issue with the arm64 HUGETLB code.
I wasn't able to trigger the issue over the weekend on a kernel with
HUGETLBFS disabled. There are known issues with our handling of
contiguous entries, and this might be an artefact of that.
I'll see if I can narrow this down any further.
Thanks,
Mark.
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WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com>
To: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
will.deacon@arm.com, catalin.marinas@arm.com,
punit.agrawal@arm.com
Subject: Re: Bad page state splats on arm64, v4.11-rc{3,4}
Date: Mon, 3 Apr 2017 11:56:29 +0100 [thread overview]
Message-ID: <20170403105629.GB18905@leverpostej> (raw)
In-Reply-To: <20170331175845.GE6488@leverpostej>
On Fri, Mar 31, 2017 at 06:58:45PM +0100, Mark Rutland wrote:
> Hi,
>
> I'm seeing intermittent bad page state splats on arm64 with 4.11-rc3 and
> v4.11-rc4. I have not tested earlier kernels, or other architectures.
>
> So far, it looks like the flags are always bad in the same
> way:
>
> bad because of flags: 0x80(waiters)
>
> ... though I don't know if that's definitely the case for splat 4, the
> BUG at mm/page_alloc.c:800.
>
> I see this in QEMU VMs launched by Syzkaller, triggering once every few
> hours. So far, I have not been able to reproduce the issue in any other
> way (including using syz-repro).
It looks like this may be an issue with the arm64 HUGETLB code.
I wasn't able to trigger the issue over the weekend on a kernel with
HUGETLBFS disabled. There are known issues with our handling of
contiguous entries, and this might be an artefact of that.
I'll see if I can narrow this down any further.
Thanks,
Mark.
next prev parent reply other threads:[~2017-04-03 10:56 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-31 17:58 Bad page state splats on arm64, v4.11-rc{3,4} Mark Rutland
2017-03-31 17:58 ` Mark Rutland
2017-03-31 17:58 ` Mark Rutland
2017-04-03 10:56 ` Mark Rutland [this message]
2017-04-03 10:56 ` Mark Rutland
2017-04-03 10:56 ` Mark Rutland
2017-04-03 11:37 ` Will Deacon
2017-04-03 11:37 ` Will Deacon
2017-04-03 11:37 ` Will Deacon
2017-04-03 15:48 ` Catalin Marinas
2017-04-03 15:48 ` Catalin Marinas
2017-04-03 15:48 ` Catalin Marinas
2017-04-03 15:51 ` Mark Rutland
2017-04-03 15:51 ` Mark Rutland
2017-04-03 15:51 ` Mark Rutland
2017-04-03 17:43 ` Mark Rutland
2017-04-03 17:43 ` Mark Rutland
2017-04-03 17:43 ` Mark Rutland
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