how to record a kernel error

[marosg]

Today my raspbian crashed three times at the same spot, when copying file over ssh. On the screen I saw a message like "BUG in kernel" and there was also .c file and line number. Of course I don't remember. After reboot I cannot find this error anywhere in /var/log. Where to look if I want to report it ? Is the only option to write down what I see on the screen ?

[marosg]

hmmm, no response. as usual

Here is the error, I get it EVERY time I do scp, after it copies couple of MB.

skb_over_panic
Kernel BUG at net/core/skbuff.c:128
Unable to handle kernel NULL pointer dereference at virtual address 00000000

[RaTTuS]

what is your Volt measurement over tp1 / tp2
what PSU are you using
what devices have you got attached
do you get any errors if you
tail -f /var/log/syslog
and ru it again ?

[Serac]

Here is the error, I get it EVERY time I do scp, after it copies couple of MB.

skb_over_panic
Kernel BUG at net/core/skbuff.c:128
Unable to handle kernel NULL pointer dereference at virtual address 00000000

Gut feeling is that you have managed to trigger a buffer overrun. What would help is the full log including any stack trace that precedes the "skb_over_panic: text: <yadda>" along with the kernel version (guessing 3.1.9).

If the console is still up and running, do a "dmesg > ~/kernel.log" and post the tail end after a reboot. You could also try upgrading to a 3.2.xx kernel in case this bug has already been fixed in the mainline tree.

[marosg]

Problem is the computer is dead after I get this. Al I can do is to have a look at the screen, if I started that scp command there I see the messages. Other than that I can only unplug the power.
And BTW, it is the first message I see.

I did more googling and it looks like it happened to people in 2009 and 2010 using the usb wifi driver I use (p54usb). Looks like it can crash when flooded with packets. Interesting thing is, when I do apt-get update or wget something from internet, I never get a problem. It is just local scp that brings it down. Is there any way how to limit scp bandwidth ? I can try that.

Somebody asked about power, I use powered HUB. When I did not, kernel could see the wifi, but was not able to do anything with it, so obviously more power is needed.

[Serac]

Code: Select all

man scp

SYNOPSIS
scp [-1246BCpqrv] [-c cipher] [-F ssh_config] [-i identity_file] [-l limit] [-o ssh_option]
[-P port] [-S program] [[user@]host1:]file1 ... [[user@]host2:]file2
[...]
-l limit
Limits the used bandwidth, specified in Kbit/s.

Also worth looking at the -C flag to enable compression which might help, or it may cause one end of the link to bog down.