tree 1b7a8a03aa73fa42799717df16c7d8cdacf04e8e
parent 6ba4431012a7ceeb0570a223ce4a67843bbb6353
author Patrick Williams <patrick@stwcx.xyz> 1680715623 -0500
committer Patrick Williams <patrick@stwcx.xyz> 1680724583 -0500

event: prevent potential deadlock

In the `obtain_lock<true>()` path there is a race in which another
thread can run after the `run_condition.signal()` call before the
mutex lock call is executed.  This other thread could run a significant
amount of code, including coming around to be back in the `run_one`
path.

To prevent this behavior, add a stage to the lock so that there is an
ordering such that the signalling thread is ensured to get the primary
lock before the signalled thread.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia464a95ed55246a67ed87601275a6e1fa8b16ba3