Re: 2.6.24-sha1: RIP [<ffffffff802596c8>] iov_iter_advance+0x38/0x70

[Alexey Dobriyan <adobriyan@gmail.com>]

On Wed, Feb 13, 2008 at 03:42:02PM +1100, Nick Piggin wrote:
> On Wednesday 13 February 2008 11:17, Nick Piggin wrote:
> > On Wednesday 13 February 2008 09:27, Alexey Dobriyan wrote:
> 
> > > It's a trivial dumb module which does nothing but loads and unloads.
> > > I redid ftest03 later without any suspicious activity and it oopsed the
> > > same way.
> >
> > Ah crap. Hmm, maybe I didn't consider all cases with my last patch to
> > that code... is there an easy way to get the ftest03 source and run
> > it?
> 
> OK I didn't realise it is a test from ltp.
> 
> But I can't reproduce it for the life of me with the latest git kernel
> and latest ltp tarball.
> 
> Is it easy to reproduce?

Well, yes. SMP, non-preemptible kernel, (and maxcpus=1 really helps!)

	while true; do
		./ftest03
	done

This alone seems stable, but starting whole LTP in parallel downs the box
very quickly.

> Are you reproducing it simply by running the
> ftest03 binary directly from the shell? How many times between oopses?
> It is multi-process but no threads, so races should be minimal down
> this path -- can you get an strace of the failing process?

so far it generates too many output, trying to reduce testcase.

Patch doesn't help here, too.