[Concurrency] Fix unsafe continuation validation when a continued task has been destroyed. #75274
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…k has been destroyed. SWIFT_DEBUG_VALIDATE_UNCHECKED_CONTINUATIONS works by tracking the context pointers of active continuations, and verifying that a resumed context is in the set of active continuations. However, the resume calls are passed the task pointer, not the context pointer. The context pointer is recovered from the task. If the task has been destroyed, the context pointer is invalid. This can result in a weird error message or it can crash if the context pointer is used before checking it against the active continuations. Instead, track tasks that are suspended pending an unchecked continuation. If the task is destroyed, we'll still be passed the dangling pointer and check that pointer against the tracking info. We must be sure to check that before trying to use anything inside it. rdar://131858544
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@swift-ci please test |
ktoso
approved these changes
Jul 19, 2024
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SWIFT_DEBUG_VALIDATE_UNCHECKED_CONTINUATIONS works by tracking the context pointers of active continuations, and verifying that a resumed context is in the set of active continuations. However, the resume calls are passed the task pointer, not the context pointer. The context pointer is recovered from the task. If the task has been destroyed, the context pointer is invalid. This can result in a weird error message or it can crash if the context pointer is used before checking it against the active continuations.
Instead, track tasks that are suspended pending an unchecked continuation. If the task is destroyed, we'll still be passed the dangling pointer and check that pointer against the tracking info. We must be sure to check that before trying to use anything inside it.
rdar://131858544