Commits on Sep 10, 2018

1. Fix deadlock in dispatcher …

   There was a rare case where the dispatcher could end up deadlocked when
   calling stop, which would cause the whole leadership change procedure to
   go sideways, the dispatcher to pile up with goroutines, and the node to
   crash.
   
   In a nutshell, calls to the Session RPC end up in a (*Cond).Wait(),
   waiting for a Broadcast that, once Stop is called, may never come. To
   avoid that case, Stop, after being called and canceling the Dispatcher
   context, does one final Broadcast to wake the sleeping waiters.
   
   However, because the rpcRW lock, which stops Stop from proceeding until
   all RPCs have returned, was previously obtained BEFORE the call to
   Broadcast, Stop would never reach this final Broadcast call, waiting on
   the Session RPCs to release the rpcRW lock, which they could not do
   until Broadcast was called. Hence, deadlock.
   
   To fix this, we simple have to move this final Broadcast to above the
   attempt to acquire the rpcRW lock, allowing everything to proceed
   correctly.
   
   Signed-off-by: Drew Erny <[email protected]>

   

   dperny committed Sep 10, 2018
   Configuration menu

   • View commit details
   • Copy full SHA for 4f15251
   • Browse repository at this point

   Copy the full SHA

   4f15251 View commit details

   Browse the repository at this point in the history