Where can I get help for debugging system crash ?

[Matthew Seaman]

On 21/12/2016 14:00, Manish Jain wrote:
> I am running a FreeBSD 11 amd64 box. The box generally works well, but 
> once every while (about once a month), the system produces a crash, with 
> a large core file at /var/crash. I had a crash yesterday. The info.0 for 
> the the last core reads as :
> 
> Dump header from device: /dev/ada0p3
>    Architecture: amd64
>    Architecture Version: 2
>    Dump Length: 1012834304
>    Blocksize: 512
>    Dumptime: Tue Dec 20 19:05:28 2016
>    Hostname: bourne.1dent1ty
>    Magic: FreeBSD Kernel Dump
>    Version String: FreeBSD 11.0-RELEASE-p1 #0 r306420: Thu Sep 29 
> 01:43:23 UTC 2016
>      root at releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC
>    Panic String: page fault
>    Dump Parity: 4025560426
>    Bounds: 0
>    Dump Status: good
> 
> /dev/ada0p3 corresponds to my swap partition. My box has 2 solid state 
> disks, which provide ada0p1 (efi), ada0p2 (ufs), ada0p3 (swap), ada0p4 
> (ufs) and ada1s1 (ufs).
> 
> I need help to determine exactly what is producing the crash - Is it 
> some hardware problem or some issue with the FreeBSD code ? If anyone 
> can help me get through to the right channel, I will be grateful indeed.

Hi, Manish,

The best thing to do here is to open a PR with what details of the crash
you can extract from the core dump.  You have a full system core, so you
should be able to follow the instructions here, and extract a backtrace
from the kernel:

https://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug-gdb.html

Or generating a textdump will automatically process your saved core and
produce a textual report with lots of debugging information.  This does
require a modified kernel configuration though.  See
textdump(4) and http://www.etinc.com/122/Using-FreeBSD-Text-Dumps for
details.

If you can pin the problem down to a particular subsystem or device,
then that should indicate which mailing list would be a good choice to
discuss the problem.  If it doesn't appear to be in any device or
sub-system specific part of the kernel, then try asking on
freebsd-stable at ...

	Cheers,

	Matthew


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