Re: s390 hugetlb oops with libhugetlbfs test-suite

[Nishanth Aravamudan <nacc@us.ibm.com>]

On 29.07.2008 [19:22:43 +0200], Gerald Schaefer wrote:
> On Fri, 2008-07-25 at 20:41 -0700, Nishanth Aravamudan wrote:
> > Odd, this is the same kernel as last time, which wasn't tainted. The reason for
> > the taint is the following:
> > 
> > ------------[ cut here ]------------
> > Badness at drivers/s390/cio/qdio_main.c:1361
> 
> Hi,
> 
> This was fixed by our qdio developer recently, but the fix is not yet
> upstream. However, I doubt that this is related to the hugetlbfs problem.

Yeah, it didn't seem related, and the first dump I posted didn't trigger
that badness.

> I was able to reproduce the "Bad page state", with the current libhugetlbfs
> development snapshot and your patch for s390. It only happened on machines
> with software large page emulation, but we certainly have a problem there.
> Thanks for reporting this bug and adding s390 support to libhugetlbfs, I
> will look into this problem.

Just FYI, I've merged up the patch that adds support and it is in the
latest development snapshot of libhugetlbfs:
http://libhugetlbfs.ozlabs.org/snapshots/libhugetlbfs-dev-20080729.tar.gz.
Beyond the counters case, I saw one other issue on s390 (haven't
confirmed if it happens anywhere else), the icache-hygiene test, when
run manually a few times, will fail every so often claiming that one of
the mmap()s returned ENOMEM. I haven't had time to track that down yet,
but it might be because of the address space layout and the size of the
hugepage on s390.

Thanks,
Nish

-- 
Nishanth Aravamudan <nacc@us.ibm.com>
IBM Linux Technology Center