tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Help with ddb and lockdebug.



        Hello.  I'm trying to debug akernel module I'm working on which is
having locking issues.  I have a 5.0 kernel with  options LOCKDEBUG turned
on, and I'm able to figure out some of what I'm seeing, but I have a couple
of questions, and I hope someone here can help point me in the right
direction so I can make further progress on getting zaptel working on
NetBSD-5.x.  
I'm seeing output like the following and I have a couple of questions:

Mutex error: lockdebug_barrier: spin lock held

lock address : 0x00000000c0b24700 type     :               spin
initialized  : 0x00000000c043a946
shared holds :                  0 exclusive:                  1
shares wanted:                  0 exclusive:                  0
current cpu  :                  1 last held:                  1
current lwp  : 0x00000000ce0a7520 last held: 0x00000000ce0a7520
last locked  : 0x00000000c043a8a6 unlocked : 0x00000000c04280f3
owner field  : 0x0000000000010700 wait/spin:                0/1

        1.   What are the pointers for the locked and unlocked fields?  Are
they pointers to the struct proc structures for the last processes that
locked and unlocked this lock respectively?  If so, how can I examine those
proc structures in ddb?

2.  How do I read the owner field?  It doesn't look like a uid or a pid,
what is it?

3.  Is there documentation on some of this somewhere?  I've read the ddb
man page, and I'm familiar with the 4.4BSD internals book by Kirk Mcusick.
I've been working with NetBSD for years, but I'm having trouble finding
where this output comes from in the source tree.

        In short, if anyone has pointers on how I can get more complete
information on what I'm looking at in ddb, I would be very interested.

-thanks
-Brian



Home | Main Index | Thread Index | Old Index