Hi Kent,
Am 03.01.2013 um 23:25 schrieb Kent A. Reed:

> [Oops - I responded to Joachim and forgot about the list. This is a resend.]
> 
> On 1/3/2013 3:42 PM, Joachim Franek wrote:
>>> I have also observed the crashes after about 5min.
>>> But after several reboots I was able to run
>>> the cnc demo programm from sim/axis/axis_mm.
> 
> Hi, Joachim. I'm the KAR. I've traced my crashes to the way my 
> BeagleBone and DHCP server are interacting. I'm not sure yet what the 
> root cause is but I am sure it's not in Michael's 
> LinuxCNC/Xenomai/Ubuntu system since the same occurs when I network-boot 
> a Ubuntu Quantal system from the same server. It does not happen when I 
> boot /load everything directly from microSD card.
> 
> When you say "after several reboots" do you mean your crashes go away? I 
> never saw that. My systems reliably "die" at about 4 minutes (I just run 
> 'top', wait for the lockup, and read the last recorded time) and I can 
> get a different lifetime by changing the default client-lease time in 
> the DHCP server. Having a lease expire should not make a client lock up. 
> Like I said, I'm not sure what the root cause is yet.

to nail this, tcpdump might be helpful - 'sudo apt-get install tcpdump' if 
needed

useful idioms:

trace traffic from/to a specific MAC address:  tcpdump -i br0 -vvv ether host 
00:18:31:8e:ee:41

more specific filters:
DHCP: tcpdump -i br0 -vvv port bootpc or  port bootps
TFTP: tcpdump -i br0 -vvv  port tftp
NFS mount issues:  tcpdump -i br0 -vvv port 111 or port 2049

for tracking NFS mount problems, this might help: 
http://stromberg.dnsalias.org/~strombrg/NFS-troubleshooting-2.html

here's a trace of the start of the DHCP exchange of a beaglebone with the DHCP 
server:


alix:~# tcpdump -i br0 port bootps -vvv
tcpdump: listening on br0, link-type EN10MB (Ethernet), capture size 65535 bytes

08:33:00.910137 IP (tos 0x0, ttl 255, id 1, offset 0, flags [DF], proto UDP 
(17), length 328)
    0.0.0.0.bootpc > 255.255.255.255.bootps: [no cksum] BOOTP/DHCP, Request 
from 00:18:31:8f:4f:e4 (oui Unknown), length 300, xid 0x318f6415, secs 5, Flags 
[none] (0x0000)
          Client-Ethernet-Address 00:18:31:8f:4f:e4 (oui Unknown)
          file "/boot/uImage"
          Vendor-rfc1048 Extensions
            Magic Cookie 0x63825363
            DHCP-Message Option 53, length 1: Discover
            MSZ Option 57, length 2: 576
            Parameter-Request Option 55, length 3: 
              Subnet-Mask, Default-Gateway, Domain-Name-Server
            END Option 255, length 0
            PAD Option 0, length 0, occurs 47
08:33:00.911150 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP 
(17), length 328)
    alix-intern.stiwoll.mah.priv.at.bootps > bb1.stiwoll.mah.priv.at.bootpc: 
[udp sum ok] BOOTP/DHCP, Reply, length 300, xid 0x318f6415, secs 5, Flags 
[none] (0x0000)
          Your-IP bb1.stiwoll.mah.priv.at
          Server-IP alix-intern.stiwoll.mah.priv.at
          Client-Ethernet-Address 00:18:31:8f:4f:e4 (oui Unknown)
          file "nfsroot/bb-ubuntu/boot/vmlinuz-3.2.21-xenomai+"
          Vendor-rfc1048 Extensions
            Magic Cookie 0x63825363
            DHCP-Message Option 53, length 1: Offer
            Server-ID Option 54, length 4: alix-intern.stiwoll.mah.priv.at
            Lease-Time Option 51, length 4: 36000
            Subnet-Mask Option 1, length 4: 255.255.255.224
            Default-Gateway Option 3, length 4: alix-intern.stiwoll.mah.priv.at
            Domain-Name-Server Option 6, length 8: 
alix-intern.stiwoll.mah.priv.at,mail.mah.priv.at
            END Option 255, length 0
            PAD Option 0, length 0, occurs 22

etc etc

- Michael


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