FreeBSD 6.3 deadlock (vm_map?) with DDB output

Stef stef at
Mon Jun 30 23:16:15 UTC 2008

John Baldwin wrote:
> On Sunday 15 June 2008 07:23:19 am Stef Walter wrote:
>> I've been trying to track down a deadlock on some newish production
>> servers running FreeBSD 6.3-RELEASE-p2. The deadlock occurs on a
>> specific (although mundane) hardware configuration, and each of several
>> servers running this hardware deadlock about once per week.
> Try this change:
> We use it at work on 6.x.  W/o this fix, round-robin stops working on 4BSD 
> when softclock() (swi4: clock) blocks on a lock like Giant.

Just wanted to confirm: That patch did the trick. All the SMP machines
that had this problem have been stable for 11 days now, longer than any
of them were up previously.

I changed the patch slightly to work with FreeBSD 6.3-RELEASE. That's
attached, in case anyone needs this later.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: kern_sched4bsd_deadlock.patch
Type: text/x-patch
Size: 2036 bytes
Desc: not available
Url :

More information about the freebsd-hackers mailing list