Just catching up on these threads. These two variables should simply be
volatile, right?
Matthew Bellew wrote:
FlowController.incrementRequestCount() and
FlowController.decrementRequestCount() access the variables
_requestCount and _maxConcurrentRequestCount outside of any
synchronized block. This makes it possible to _requestCount,
especially on a multi-processor machine. The subtlety of this bug is
that --_requestCount and ++_requestCount look atomic, but they are not.
In particular, we have an action that returns images. Since some
pages contain many images, this controller can be hit my many requests
concurrently from the same session. We hit the
decrementRequestCount() assert quite frequently in production.
assert _requestCount > 0 : request.getRequestURI();
Thanks,
Matt
