RE: Kernel boot hangs by parallel flood pings

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@interfaceconcept.com])
---- Original message -----
RE: FCC ethernets not stable

I received the right solution from Jean-Denis Boyer (thanks to him...)

quoted

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

quoted

I never saw this problem after installing this patch.

Regards
Gerard Guevel=20

-----Original Message-----
From: linuxppc-embedded-bounces@ozlabs.org=20
[mailto:linuxppc-embedded-bounces@ozlabs.org] On Behalf Of=20
Steffen Rumler
Sent: Wednesday, January 12, 2005 02:38
To: linuxppc
Subject: Kernel boot hangs by parallel flood pings
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I'm using a 2.4.20 kernel (PPC).
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When I run multiple 'ping -f' directed to my board
during the kernel boots, sometimes it hangs with
the following messages:
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   Memory BAT mapping: BAT2=3D64Mb, BAT3=3D32Mb, residual: 84Mb
   Linux version 2.4.20-rthal5 (ru@styx) (gcc version 2.95.3=20
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=3Daps0=20
ip=3D218.1.36.70:218.1.36.47:218.1.36.254:255.255.255.0::eth0:off
   panic=3D1 mem=3D119436k
   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
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I have checked this with the BDI2000 and found that the
kernel loops anywhere inside ip_route_input().
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I think this is because the ethernet driver (fcc_enet.c)
enables the hardware too already inside it's init routine=20
(fec_enet_init()).
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In this way, frames may be received and forwarded to the upper
layers with netif_rx(), before the TCP/IP was initialized.
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I suggest to delay the lines
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   /* Enable transmit/receive */
   fccp->fcc_gfmr |=3D FCC_GFMR_ENR | FCC_GFMR_ENT;
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to the open entry point (fcc_enet_open()), which is
triggered by 'ifconfig up' in the following way:
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   if(!((fccp->fcc_gfmr) & FCC_GFMR_ENR))
      fccp->fcc_gfmr |=3D (FCC_GFMR_ENR | FCC_GFMR_ENT);
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By the way, fcc_enet_close() does _NOT_ stop the hardware.
Hopefully, this is not a real problem.
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Steffen
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--=20
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--------------------------------------------------------------
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Steffen Rumler
ICN CP D NT SW 3
Siemens AG
Hofmannstr. 51                 Email: Steffen.Rumler@siemens.com
D-81359 Munich                 Phone: +49 89 722-44061
Germany                        Fax  : +49 89 722-36703
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--------------------------------------------------------------
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