Re: Linux 2.6.20-rc4
From: Linus Torvalds
Date: Sun Jan 07 2007 - 17:50:42 EST
On Sun, 7 Jan 2007, Peter Osterlund wrote:
> Linus Torvalds <torvalds@xxxxxxxx> writes:
>
> > Patrick McHardy (2):
> > [NETFILTER]: New connection tracking is not EXPERIMENTAL anymore
>
> I get kernel panics when doing large ethernet transfers. A loop doing
> continuous scp transfers of some large (>100MB) files makes the kernel
> crash after a few minutes. scp runs on a different machine and copies
> data from the machine that crashes. (The first crash did not happen
> when scp was used, but scp is an easy way to reproduce the problem.)
>
> I've seen this crash also with 2.6.20-rc2-git-something. Previously I
> ran these kernels quite a lot and used a ppp link without problems.
> Today I started using eth0 and the crashes started to occur. I have
> netfilter rules for ppp0, but no rules for eth0. Earlier kernels have
> been working perfectly for large eth0 transfers on this machine.
>
> Hand copied data from the console:
>
> BUG: unable to handle kernel paging request at virtual address 9f5cea9f
> printing eip:
> c034c729
> *pde = 00000000
> Ooops: 0000 [#1]
> PREEMPT
> Modules linked in: ... 8139too ...
> CPU: 0
> EIP: 0060:[<c034c729>] Not tainted VLI
> EFALLGS: 00010206 (2.6.20-rc4 #13)
> EIP is at ipv4_conntrack_help+0x6b/0x83
> eax: c0475e44 ebx: 9f5cea37 ecx: d1dcebb0 edx: 00000014
> esi: d1dcebb0 edi: c0475e44 ebp: c0475dd8 esp: c0475dc4
That's
and $0xf,%dl
movzbl %dl,%edx
lea (%ecx,%edx,4),%edx
movzbl %bl,%eax
mov %eax,(%esp)
mov %esi,%ecx
mov %edi,%eax
mov 0xfffffff0(%ebp),%ebx
** call *0x68(%ebx) **
add $0x8,%esp
pop %ebx
pop %esi
pop %edi
pop %ebp
ret
which is ipv4_conntrack_help():
return help->helper->help(pskb,
(*pskb)->nh.raw - (*pskb)->data
+ (*pskb)->nh.iph->ihl*4,
ct, ctinfo);
and that call instruction is the one that oopses because "help->helper" is
corrupt (it's 0x9f5cea37 - not a valid kernel pointer).
David, there really *is* something screwy in netfilter.
Linus
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