Fix dropping TLS for detached futures #139
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When a detached future is being cleaned up after the end of an execution, it won't be able to access the current task's storage any more. We need to bail out early from the cleanup to avoid a panic.
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| // If we've finished execution already (this task was detached), don't clean up. We | ||
| // can't access the state any more to destroy thread locals, and don't want to run | ||
| // any more wakers (which will be no-ops anyway). | ||
| if ExecutionState::try_with(|state| state.is_finished()).unwrap_or(true) { | ||
| return Poll::Ready(()); | ||
| } |
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Why are we still polling the future if execution already finished?
Was the task's local storage already dropped in ExecutionState::cleanup when we drained tasks?
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We're not re-polling the future after execution finishes. But at ExecutionState::cleanup time, we drop the continuation, which for unfinished tasks involves resuming the task so that it can unwind its stack. That's how we end up in this code. We do still clean up the task's local storage inExecutionState::cleanup, so this change isn't actually leaking anything, just changing where the cleanup happens.
jorajeev
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Mar 7, 2024
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| struct ShuttleSpawn; | ||
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| impl Spawn for ShuttleSpawn { |
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Nice - didn't know about the Spawn trait.
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The Shuttle issue was fixed by awslabs/shuttle#139 Signed-off-by: James Bornholt <bornholt@amazon.com>
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The Shuttle issue was fixed by awslabs/shuttle#139 Signed-off-by: James Bornholt <bornholt@amazon.com>
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When a detached future is being cleaned up after the end of an
execution, it won't be able to access the current task's storage any
more. We need to bail out early from the cleanup to avoid a panic.
I also fixed two small issues:
Span::recordcall, despite only specifying an earlier version.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.