There was a very slim chance of a race between isc_socket_detach and
process_fd: isc_socket_detach decrements references to 0, and before it
calls destroy gets preempted. Second thread calls process_fd, increments
socket references temporarily to 1, and then gets preempted, first thread
then hits assertion in destroy() as the reference counter is now 1 and
not 0.
Even though statistics are lockless they still use atomics which
might cause contention. Split stats counters into buckets, sharded
by an artificial thread identifier, to increase throughput.
Creation of EVP_MD_CTX and EVP_PKEY is quite expensive, until
we fix the code to reuse the context and key we'll use our own
implementation of siphash.
isc_task_pause/unpause were inherently thread-unsafe - a task
could be paused only once by one thread, if the task was running
while we paused it it led to races. Fix it by making sure that
the task will pause if requested to, and by using a 'pause reference
counter' to count task pause requests - a task will be unpaused
iff all threads unpause it.
Don't remove from queue when pausing task - we lock the queue lock
(expensive), while it's unlikely that the task will be running -
and we'll remove it anyway in dispatcher
Add checks to the kasp system test to verify CDNSKEY publication.
This test is not entirely complete, because when there is a CDNSKEY
available but there should not be one for KEY N, it is hard to tell
whether the existing CDNSKEY actually belongs to KEY N or another
key.
The check works if we expect a CDNSKEY although we cannot guarantee
that the CDNSKEY is correct: The test verifies existence, not
correctness of the record.
Witold Kręcicki
Matthijs Mekking