Fix use-after-free on panic during ArcWake::wake_by_ref #1797
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Nice! Would you mind adding a test for this? |
Wrap temporary `Arc<>`s in `ManuallyDrop` early instead of calling `forget()` later: that way even during unwinding for panics it doesn't drop the refcount it doesn't actually own. Also it means `wake_by_ref` doesn't need an unwind section anymore. Same thing in `increase_refcount` (although `Arc::clone` should only abort, not unwind).
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Added a test (if you prefer it in a separate commit before/after the fix I can split it of course). The test fails for me without the fix applied: |
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Wonderful, thank you! |
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Wrap temporary
Arc<>s inManuallyDropearly instead of callingforget()later: that way even during unwinding for panics it doesn't drop the refcount it doesn't actually own.Also it means
wake_by_refdoesn't need an unwind section anymore.Same thing in
increase_refcount(althoughArc::cloneshould only abort, not unwind).