Each network thread holds an array of locks, indexed by a hash
of fd. When we accept a connection we hold a lock in accepting thread.
We then generate the thread number and lock bucket for the new
connection socket - if we hit the same thread and lock bucket as
accepting socket we get a deadlock. Avoid this by checking if we're
in the same thread/lock bucket and not locking in this case.
5235. [cleanup] Refactor lib/isc/app.c to be thread-safe, unused
parts of the API has been removed and the
isc_appctx_t data type has been changed to be
fully opaque. [GL #1023]
The option `update-check-ksk` will look if both KSK and ZSK are
available before signing records. It will make sure the keys are
active and available. However, for operational practices keys may
be offline. This commit relaxes the update-check-ksk check and will
mark a key that is offline to be available when adding signature
tasks.
In dns_rpz_update_from_db we call setup_update which creates the db
iterator and calls dns_dbiterator_first. This unpauses the iterator and
might cause db->tree_lock to be acquired. We then do isc_task_send(...)
on an event to do quantum_update, which (correctly) after each iteration
calls dns_dbiterator_pause, and re-isc_task_sends itself.
That's an obvious bug, as we're holding a lock over an async task send -
if a task requesting write (e.g. prune_tree) is scheduled on the same
workers queue as update_quantum but before it, it will wait for the
write lock indefinitely, resulting in a deadlock.
To fix it we have to pause dbiterator in setup_update.
Ondřej Surý
Witold Kręcicki
Mark Andrews
Tinderbox User
Evan Hunt
Michał KępieńandEvan Hunt
Tony FinchandEvan Hunt
Matthijs Mekking