Re: next-20130117 - kernel BUG with aio

[Kent Overstreet <koverstreet@google.com>]

On Thu, Jan 24, 2013 at 02:25:37PM -0800, Zach Brown wrote:
> > No, I didn't see that bug until after I'd fixed the other three, but as
> > far as I can tell everything's fixed with the patches I'm about to mail
> > out - my test VM has been running for the past two days without errors,
> > it's kill -9'ing a process that's got iocbs in flight to a loopback
> > device every two seconds.
> 
> I'm really worried that this patch series hasn't seen significant enough
> testing to justify being queued.
> 
> I'll be first in line for blame for not finding the time to finish my
> review of the series.
> 
> What specific tests has this gone through?  The aio tests in xfstests /
> ltp?  (And as you discovered while chasing this bug, whatever platform
> you were running on doesn't seem slow enough to catch some paths.. run
> all the tests over loop?)

I have run xfstests on real hardware - though that didn't catch this
either. These patches are all queued up for our internal tree (I need to
bug Ted to review them... and add these latest fixes). And aio is used
heavily enough internally that if I screwed anything up, I'll be on the
hook...

> Jeff, can you suggest a more modern testing regime for the aio core?
> It's been so long since I had to hammer on this stuff..

I'm wondering how much it'd buy us to rig up fault injection (I've got
some awesome dynamic fault injection code I need to push upstream...).
I'll try and test with that in the next day or so, though.

There's some people here that'd been working on code coverage tooling
too, I should probably learn how to work that stuff.