ffs snapshot lockup

[Vivek Khera]

On Sep 22, 2006, at 4:36 PM, Kris Kennaway wrote:

> Start by enabling INVARIANTS, INVARIANT_SUPPORT, DEBUG_LOCKS and
> DEBUG_VFS_LOCKS, then run 'show lockedvnods' and 'alltrace' in DDB
> (spammy, need that serial console), or at least trace the running
> processes (show allpcpu) and those listed in lockedvnods.  Then call
> doadump and save the core+kernel.debug when you reboot.

Well, what an exciting weekend we had!  Three lockups/panics: two  
during running a dump (mksnap_ffs seems to be the culprit) and one  
running background fsck after rebooting from the prior crash.

Details are posted at http://vivek.khera.org/scratch/crashlogs/

I have the crashdumps available to a kernel hacker upon request (i'd  
rather not make them generally available to the public...)