panic: in_pcblookup_local (?)

[Robert N. M. Watson]

On 2 May 2013, at 01:57, Glen Barber wrote:

> So, I am admittedly not too familiar with DDB.  In fact, I just now
> realize the kernel is built without DDB...

DDB is a very powerful tool in that it's been custom-developed to help debug common kernel panics. It lacks some of the flexibility, and especially the data-type awareness of GDB, but GDB is a less well-suited tool when investigating common crash patterns. I'll usually start out debugging in DDB, and find that 90% of my in-development panics can be debugged with it, resorting to GDB for post-mortem analyses in production or particularly hard debugging cases (usually where DDB's pretty printers for data types fall short). I've wanted, for a long time, to teach DDB how to pretty-print arbitrary types using DTrace's CTF meta-data, which would address the most significant major case where I turn to GDB. Mind you, the limitations I see in GDB are made up for in most part by John's GDB scripts :-).

>> Put those in a dir and do 'source gdb6'.  You can then run 'ps' to get a good 
>> ps listing that includes threads.  You can also use 'thread apply all bt' to 
>> get stacktraces of all threads in kgdb.  I believe there is an 'allpcpu' 
>> command that is similar to 'show allpcpu' in DDB.
> 
> I have the outputs of 'ps', 'allpcpu', and 'thread apply all bt' saved
> to separate script(1) files.  Is there anything in particular I can look
> for before uploading the files somewhere public?  At quick-ish look
> though, I did not see anything cf-agent (the current process at time of
> panic) related.

To be honest, it's probably easiest if I just take a look at it and see what I see. In as much as I find interesting things, I'll follow up explaining what they are. We may find we can't track this problem down from the data we have -- but it's worth a try.

Robert