Re: Stable panic on shutdown: swapoff: failed to locate N swap blocks

On Fri, Oct 15, 2004, Andrey Chernov wrote:
> On Fri, Oct 15, 2004 at 01:11:45PM -0400, David Schultz wrote:
> > On Fri, Oct 15, 2004, Andrey Chernov wrote:
> > > N of blocks can be different.
> > > Can't provide full debugging trace yet, excepting this one:
> > 
> > The traceback won't be very helpful in this case because this most
> > likely indicates a swap leak that happened some time earlier.
> > What *would* be helpful is more information about your swap
> > devices, any steps you need to take while the system is running to
> > reproduce this, the approximate size of N, etc.
> 
> # swapinfo
> Device          1K-blocks     Used    Avail Capacity
> /dev/da0s1b        615408    41408   574000     7%
> 
> Nothing special to reproduce, it is always reproduced automatically at 
> shutdown.

You're clearly using some of that swap space for something, so it
would be great if you could narrow it down a bit more.  For
instance, does the problem only occur if you shut the system down
after having run particular applications?  Are there ever any disk
errors?

I'll poke around and see if I can find anything by inspection.
phk's rotitilling of the swap subsystem introduced a number of new
nits, but no serious bugs that I can see...

> Kernels from Aug 8 and below never do that, I see this panic constantly 
> only with most recent kernels (last 2 days). I not test kernels between 
> Aug 8 and last 2 days, so can't say anything.

The bug was probably introduced earlier, either by me, Alan, or
phk, but the swapoff codepath wasn't routinely exercised until
recently.