Re: Linux 2.6.25-rc4

[Jens Axboe <jens.axboe@oracle.com>]

On Thu, Mar 06 2008, Bartlomiej Zolnierkiewicz wrote:
> On Thursday 06 March 2008, Ingo Molnar wrote:
> > 
> > * Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> wrote:
> > 
> > > The problem looks very similar to the one recently reported by Anders:
> > > 
> > > http://lkml.org/lkml/2008/2/22/239
> > > 
> > > "Trying out 2.6.25-rc2 smartd always causes my box to hang. I can 
> > > switch vt:s and the keyboard seems to work.
> > > 
> > > Using sysrq-e I noticed a callpath open -> ext3 -> journals -> 
> > > sync_buffer -> io_scheduel -> generic_unplig_device. I'd guess the 
> > > open stems from smartd. Removing smartd from the startup, I'm now 
> > > using rc2 fine..."
> > > 
> > > Initially we thought that it is an IDE regression but after some 
> > > testing and further investigation it seems that IDE changes just made 
> > > it more likely to occur (yesterday it turned out that the kernel with 
> > > the "guilty" IDE commit sometimes boots fine).  The issue is easily 
> > > reproducible.
> > > 
> > > PS We've already verified that it is not PREEMPT related or a compiler 
> > > bug.
> > 
> > smartd is not active here though - and starting/restarting it doesnt 
> > provoke a hang.
> 
> I was a bit unclear on this, the problem is easily reproducible but _only_
> on Anders' system (I couldn't reproduce it with smartd here either).

What IO scheduler is Anders using (and does it have an impact, eg does
it hang with deadline as well)?

-- 
Jens Axboe