8:46pm Patrick McHardy said:
James Morris wrote:
---------- Forwarded message ----------
Date: Mon, 14 May 2007 08:15:50 -0700 (PDT)
From: Curtis Doty <[EMAIL PROTECTED]>
To: Linux Kernel <[EMAIL PROTECTED]>
Subject: oops in net/ipv4/icmp.c:icmp_send() with icmp_errors_use_inbound_ifaddr
Summary: On a multi-homed box, after turning on
/proc/sys/net/ipv4/icmp_errors_use_inbound_ifaddr, it now periodically oopses
when trying to lookup the source address to use for sending an ICMP in response
to a jump ipt_REJECT.
I'm still trying to figure out what makes this test case unique. It spuriously
occurs with many fedora builds of 2.6.{18,19,20} all of which don't appear to
have any patches in this area of the kernel. Just _maybe_ it's because of a
combination of dogleg routing and overloading one vlan with multiple subnets:
[..]
BUG: unable to handle kernel NULL pointer dereference at virtual address
000000a8
[...]
EIP is at inet_select_addr+0x4/0x9f
eax: 00000000 ebx: f8b97046 ecx: 000000fd edx: 00000000
esi: 000000fd edi: 00000001 ebp: f71cd0ac esp: c078bc9c
ds: 007b es: 007b ss: 0068
Process swapper (pid: 0, ti=c078b000 task=c06fc480 task.ti=c0746000)
Stack: f8b97046 f601b130 c05fd0b6 f728b980 f728b980 f8b5adbb c05bcb6e c078bd74
00000003 00000003 00000246 00000246 00000000 f887e014 f8a611a6 f7c1ea80
f728b9a8 00000000 f727d220 f887e000 00000001 00000072 f7383800 f728b980
Call Trace:
[<f8b97046>] reject+0x0/0x4ae [ipt_REJECT]
[<c05fd0b6>] icmp_send+0x14d/0x39b
A REJECT target in the output chain will trigger this in combination
with icmp_errors_use_inbound_ifaddr because skb->dev is still NULL
at this point and its passed to inet_select_addr.
Indeed, thanks!
[EMAIL PROTECTED] nc kernel.org 42
BUG: unable to handle kernel NULL pointer dereference at virtual address
000000a8
printing eip:
c05fe72b
*pde = 00000000
Oops: 0000 [#1]
...
And for now, the easy userland workaround is to add '-i ! eth+ -j DROP'
just before any jumps to REJECT. This now causes delays/timeouts for any
forbidden outbound traffic. But it's better than an oops.
Now I'm off to figure out what daemon is trying to make these odd
connections...or if netfilter/conntrack is periodically scrambling its
brains.
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