6-STABLE snapshot (background fsck) lock-up

[John Baldwin]

On Thursday 17 August 2006 08:30, Eric Anderson wrote:
> On 08/17/06 07:25, Kostik Belousov wrote:
> > On Thu, Aug 17, 2006 at 07:08:31AM -0500, Eric Anderson wrote:
> >> I've seen this several times now, but this time I got a dump. 
> >> Basically, the system comes up after unclean shutdown, throws a bunch of 
> >> filesystems into the background fsck list, and begins 60 seconds later. 
> >>    After some amount of time, the system will lock up, presumably hung 
> >> waiting on locks.
> >>
> >> Here's some info:
> >> lock type bufwait: EXCL (count 1) by thread 0xffffff0128812980 (pid 804) 
> >> lock type getblk: EXCL (count 1) by thread 0xffffff0128812980 (pid 
> >> 804)Locked vnodes
> >>
> >> 0xffffff01c5c9f000: tag ufs, type VREG
> >>     usecount 1, writecount 0, refcount 13656 mountedhere 0
> >>     flags (VV_SYSTEM)
> >>     v_object 0xffffff01b09542a0 ref 0 pages 1691637
> >>      lock type snaplk: EXCL (count 1) by thread 0xffffff0128812980 (pid 
> >> 804)
> >>         ino 4, on dev label/vol4
> >>
> >>
> >>
> >> How can I use kgdb to get more debugging information from this?
> >>
> > Look at the
> > 
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug-deadlocks.html
> > for instructions for ddb.
> > 
> > What is the date of the system checkout ?
> 
> 
> 6-STABLE from ~8/12/06.
> 
> So there's not much that can be done with the vmcore?

Actually, there is stuff that can be done with the vmcore.  Download 
http://www.FreeBSD.org/~jhb/gdb.6

Then in kgdb do:

(gdb) source /path/to/6.gdb
(gdb) sleepchain 0xffffff0128812980

And see if that spits out a cycle.

-- 
John Baldwin