[6.0][Concurrency] Fix crash from calling fromTaskExecutorPreference after enqueueing job. #76780
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…after enqueueing job. After we've enqueued a job, another thread may run it and destroy it. Don't try to get the job's task executor preference when we try to schedule it. Instead, get the task executor preference before enqueueing the job, then use that preference when scheduling if necessary. Since getting the executor preference is potentially somewhat expensive (we need to search the status records for an executor preference record), only do this if the pre-compare-and-swap states look like they'll need it. rdar://136281920 (cherry picked from commit efa62e7)
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Explanation: When enqueueing a job on an actor, in certain circumstances we then retrieve the job's task executor preference as part of scheduling the work on the actor. However, it's possible for another thread to start draining the actor, run the job, and destroy it in that interval. This change fixes it by retrieving the task executor preference before enqueueing the job. |
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@swift-ci please test |
Cherry-pick of #76757 to
release/6.0.After we've enqueued a job, another thread may run it and destroy it. Don't try to get the job's task executor preference when we try to schedule it. Instead, get the task executor preference before enqueueing the job, then use that preference when scheduling if necessary. Since getting the executor preference is potentially somewhat expensive (we need to search the status records for an executor preference record), only do this if the pre-compare-and-swap states look like they'll need it.
rdar://136281920