On Fri, Aug 31, 2012 at 10:43:42AM -0700, John Stultz wrote:

On 08/30/2012 09:05 PM, Andreas Bombe wrote:

quoted

With that somewhat easy test I bisected it down to 4e8b14526 "time:
Improve sanity checking of timekeeping inputs". The latest Linus git
(155e36d40) with a revert of the bisected commit does not show the
problem.

Thanks so much for bisecting this down!
I'm guessing X is passing crazy large timespecs into select (via
WaitForSomething()) values that are catching on the ktime_t overflow
check in timespec_valid(). Previously these would be clamped to
KTIME_MAX (which basically is infinity) in the timer subsystem
before.

So the issue is the patch in question is too strict in its
validation. We want to be strict on things like timekeeping inputs,
but for timers wait to infinity is still valid.

The attached (sorry not inline, on the road) patch should fix this,
but could you verify it? (I'm running my testing concurrently)

I'm running it now and it's looking good. I did the video test again and
confirmed with strace that X was doing the giant timeout in select
again, but this time without any errors.

-- 
Andreas Bombe