Extracting useful information from kernel crashes
Minimum information for kernel problems
Familiarize yourself with
the general bug reporting procedures
first.
All of that will apply.
When reporting a kernel panic or crash, please remember:
- We need the console output on the screen.
Capture it and save it.
Serial consoles are best, but if you are on a VGA console you can
scroll the console back
and take readable pictures with a phone or camera.
- If the kernel panicked we need the traceback.
It may be displayed on the screen.
If you are at a
ddb>
prompt, type trace.
If you are running SMP, use the mach ddbcpu N command for each
of the N processors you have and repeat the trace
command for each processor.
- We need the process list.
Use the command ps to get us that.
Reports without the above information are useless.
This is the minimum we need to be able to track down the issue.
Additional information you can send
In some situations more information is desirable.
Below are outlined some additional steps you can take in certain situations:
- ... XXX boot crash? XXX
- ... XXX show regs? XXX
- If your crash appears to involve filesystems.
The following additional things would be helpful
- The output of the
ddb>
command show uvm
- The output of the
ddb>
command show bcstats
- The output of the mount command from your running machine,
so we know what filesystems are mounted and how.
- If your crash appears to involve hibernate/resume. XXX