Kernel boot hangs by parallel flood pings

[Rune Torgersen]

I have had the problem before (and so has several other people)

This is a reply I got on the old Linux PPC mailinglist last year
(from Gerard Guevel [gguevel at interfaceconcept.com])
---- Original message -----
RE: FCC ethernets not stable

I received the right solution from Jean-Denis Boyer (thanks to him...)
>>
It registers the IPv4 handling functions AFTER initializing the IP
routing
stuff.
Early packets could enter the stack and crash the system.

--- Kernel.old/net/ipv4/ip_output.c     Thu Jun  5 09:00:39 2003
+++ Kernel/net/ipv4/ip_output.c Thu Jun  5 09:00:28 2003
@@ -1087,11 +1087,11 @@

 void __init ip_init(void)
 {
-       dev_add_pack(&ip_packet_type);
-
        ip_rt_init();
        inet_initpeers();

+       dev_add_pack(&ip_packet_type);
+
 #ifdef CONFIG_IP_MULTICAST
        proc_net_create("igmp", 0, ip_mc_procinfo);
 #endif
>>

I never saw this problem after installing this patch.

Regards
Gerard Guevel 

> -----Original Message-----
> From: linuxppc-embedded-bounces at ozlabs.org 
> [mailto:linuxppc-embedded-bounces at ozlabs.org] On Behalf Of 
> Steffen Rumler
> Sent: Wednesday, January 12, 2005 02:38
> To: linuxppc
> Subject: Kernel boot hangs by parallel flood pings
> 
> I'm using a 2.4.20 kernel (PPC).
> 
> When I run multiple 'ping -f' directed to my board
> during the kernel boots, sometimes it hangs with
> the following messages:
> 
> 
>    Memory BAT mapping: BAT2=64Mb, BAT3=32Mb, residual: 84Mb
>    Linux version 2.4.20-rthal5 (ru at styx) (gcc version 2.95.3 
> 20010111 (prerelease/franzo/20010111))
>    #9 Tue Jan 11 17:09:22 CET 2005
>    On node 0 totalpages: 29859
>    zone(0): 29859 pages.
>    zone(1): 0 pages.
>    zone(2): 0 pages.
>    Kernel command line: bootdev=aps0 
> ip=218.1.36.70:218.1.36.47:218.1.36.254:255.255.255.0::eth0:off
>    panic=1 mem=119436k
>    Calibrating delay loop... 194.15 BogoMIPS
>    ...
>    NET4: Linux TCP/IP 1.0 for NET4.0
>    IP Protocols: ICMP, UDP, TCP
>    IP: routing cache ha
>                  ^^^^^^^
>                    the kernel boot hangs here
> 
> 
> I have checked this with the BDI2000 and found that the
> kernel loops anywhere inside ip_route_input().
> 
> I think this is because the ethernet driver (fcc_enet.c)
> enables the hardware too already inside it's init routine 
> (fec_enet_init()).
> 
> In this way, frames may be received and forwarded to the upper
> layers with netif_rx(), before the TCP/IP was initialized.
> 
> I suggest to delay the lines
> 
>    /* Enable transmit/receive */
>    fccp->fcc_gfmr |= FCC_GFMR_ENR | FCC_GFMR_ENT;
> 
> to the open entry point (fcc_enet_open()), which is
> triggered by 'ifconfig up' in the following way:
> 
> 
>    if(!((fccp->fcc_gfmr) & FCC_GFMR_ENR))
>       fccp->fcc_gfmr |= (FCC_GFMR_ENR | FCC_GFMR_ENT);
> 
> By the way, fcc_enet_close() does _NOT_ stop the hardware.
> Hopefully, this is not a real problem.
> 
> 
> Steffen
> 
> -- 
> 
> 
> --------------------------------------------------------------
> 
> Steffen Rumler
> ICN CP D NT SW 3
> Siemens AG
> Hofmannstr. 51                 Email: Steffen.Rumler at siemens.com
> D-81359 Munich                 Phone: +49 89 722-44061
> Germany                        Fax  : +49 89 722-36703
> 
> --------------------------------------------------------------
> 
> 
> 
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