Re: KVM induced panic on 2.6.38 & 2.6.39
From: Patrick McHardy
Date: Tue Jun 07 2011 - 18:57:20 EST
On 07.06.2011 20:31, Eric Dumazet wrote:
> Le mardi 07 juin 2011 à 17:35 +0200, Patrick McHardy a écrit :
>> The main suspects would be NAT and TCPMSS. Did you also try whether
>> the crash occurs with only one of these these rules?
>>> I've just compiled out CONFIG_BRIDGE_NETFILTER and can no longer access
>>> the address the way I was doing it, so that's a no-go for me.
>> That's really weird since you're apparently not using any bridge
>> netfilter features. It shouldn't have any effect besides changing
>> at which point ip_tables is invoked. How are your network devices
>> configured (specifically any bridges)?
> Something in the kernel does
> u16 *ptr = addr (given by kmalloc())
> ptr[-1] = 0;
> Could be an off-one error in a memmove()/memcopy() or loop...
> I cant see a network issue here.
So far me neither, but netfilter appears to trigger the bug.
> I checked arch/x86/lib/memmove_64.S and it seems fine.
I was thinking it might be a missing skb_make_writable() combined
with vhost_net specifics in the netfilter code (TCPMSS and NAT are
both suspect), but was unable to find something. I also went
through the dst_metrics() conversion to see whether anything could
cause problems with the bridge fake_rttable, but also nothing
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