On Tue, Oct 29, 2002 at 04:30:25AM +0300, kuznet@ms2.inr.ac.ru wrote:
> > I assume that the kernel is trying to use dynamic memory that has been
> > released already, right?
>
> Right.
>
> > What's next in tracing this one down?
>
> To tell what exactly driver makes this. Apparently, it continues
> to inject packets to the stack even after it has been destroyed.
>
In this case, would they be packets TO or FROM the ppp device?
(reminder: crash happens in ip_route_input_slow, called with struct
net_device *dev presumably pointing at what used to be the PPP device)
> If you did not see message "Freeing alive device", this means
> that driver unregistered it. Usual ppp seems to be sane...
No such message in logs, but "PPPIOCDETACH file->f_count=3" appears
quite often. If I understand it right, it'd mean that the ppp interface
is destroyed while having channels open to it... Does it give any
hint?
Let's try to summarize anything unusual this box has:
- pptp (PoPToP). But pptp is only userland software, how could it cause
such a problem? It merely forks pppd as a child.
- NAT, both SNAT and DNAT (for transparent redirection to a Squid), and
a lot of rules used to do traffic accounting so iptables configuration
is kind of hairy. Could it somehow cause packets to be "delayed" and
thus re-injected to the stack later than usual? (I'm probably just
talking nonsense here - sorry - trying to guess).
- assymetrical routing: packets come from clients over VPN, thus over the
PPP interface. They are routed back though a LAN interface that goes
to the satellite uplink. To do this, the route to the peer IP through
the PPP interface is deleted in the ip-up script.
Ah.. something else that could be relevant (??): I see that ifconfig
-a shows "duplicate" ppp devices e.g.:
ppp96 Link encap:Point-to-Point Protocol
inet addr:xxx.yyy.zzz.2 P-t-P:172.16.27.104 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:44238 errors:0 dropped:0 overruns:0 frame:0
TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:2192741 (2.0 Mb) TX bytes:153 (153.0 b)
ppp96 Link encap:Point-to-Point Protocol
inet addr:xxx.yyy.zzz.2 P-t-P:172.16.27.104 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
Is this "normal"?
Greets,
_Alain_
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:41 EST