From: Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
To: Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [GIT PULL][RESEND] Late KVM Updates for the 2.6.23 merge window
Date: Sat, 21 Jul 2007 08:58:12 +0300 [thread overview]
Message-ID: <46A1A074.6050803@qumranet.com> (raw)
In-Reply-To: <alpine.LFD.0.999.0707201633390.27249-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
Linus Torvalds wrote:
> On Sat, 21 Jul 2007, S.Çağlar Onur wrote:
>
>> With Linus's latest git, shutting down a guest (fired with -smp 2 -m 512) sometimes
>> ends up like [1], this occured as soon as qemu window closed.
>>
>> [1] http://cekirdek.pardus.org.tr/~caglar/kvm/dmesg.latest
>>
>
> [ 737.460654] Bad page state in process 'qemu-kvm'
> [ 737.460656] page:f5e68000 flags:0xea020000 mapping:00000000 mapcount:2 count:0
> [ 737.460657] Trying to fix it up, but a reboot is needed
> [ 737.460659] Backtrace:
> [ 737.460691] [<c0159e70>] bad_page+0x64/0x8e
> [ 737.460733] [<c015a7ee>] free_hot_cold_page+0x68/0x15a
>
> That's the "free_pages_check()", and in particular it seems to be
> "page_mapcount()" being non-zero that triggered that thing.
>
> So it looks like something in KVM isn't coherent about the mapping vs the
> usage counters..
>
>
Far more prosaic. It calls __free_page() on the cleanup path with the
page's virtual address instead of the struct page. I guess
__free_page() is happy with a zeroed out blob, which is the most likely
contents.
Trivial patch shortly.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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prev parent reply other threads:[~2007-07-21 5:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-20 17:32 [GIT PULL][RESEND] Late KVM Updates for the 2.6.23 merge window Avi Kivity
[not found] ` <1184952728548-git-send-email-avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-07-20 23:21 ` S.Çağlar Onur
[not found] ` <200707210221.34121.caglar-caicS1wCkhO6A22drWdTBw@public.gmane.org>
2007-07-20 23:37 ` Linus Torvalds
[not found] ` <alpine.LFD.0.999.0707201633390.27249-5CScLwifNT1QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
2007-07-21 5:58 ` Avi Kivity [this message]
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