Re: panic: ffs_blkfree: freeing free block

On Saturday 10 November 2007, Pieter de Goeje wrote:
> On Friday 09 November 2007, Kostik Belousov wrote:
> > On Fri, Nov 09, 2007 at 01:04:44PM +0100, Pieter de Goeje wrote:
> > > > Is anyone who had been able to trigger this panic still having
> > > > problems with recent kernels (and soft updates turned on)?  I've
> > > > checked with a few people who had been experiencing the panic and
> > > > they can no longer trigger it.
> > > >
> > > > It's at least a tiny bit possible some of the VM fixes that have gone
> > > > in addressed this problem.  We'd like to find out if anyone can still
> > > > trigger this.
> > >
> > > I can no longer reproduce it any more.
> >
> > Could anybody who was able to trigger the panic with relative ease, do
> > the binary search for the dates that
> > A. started the problem
> > B. eliminated it
> >
> > There is uneasy feeling for the bug that did such appearance and still
> > not tracked.
>
> Doing a binary search now. Might take some time though.
This commit to sys/vm/vm_object.c fixed it:

revision 1.386
date: 2007/10/18 23:02:18;  author: alc;  state: Exp;  lines: +2 -1
The previous revision, updating vm_object_page_remove() for the new page
cache, did not account for the case where the vm object has nothing but
cached pages.

Reported by:    kris, tegge
Reviewed by:    tegge

If you want I can still do a search for the commit that introduced the 
problem, but I think this gives a rather strong clue on what caused it :)

Pieter de Goeje