Wasmtime GitHub notifications bot (Apr 21 2026 at 18:52): Wasmtime GitHub notifications bot (Apr 21 2026 at 18:52):fitzgen opened PR #13166 from fitzgen:issue-13037 to bytecodealliance:main:
The
expose_gc_ref_to_wasmfunction takes ownership of a GC reference in the process of exposing it to raw Wasm code. For the DRC collector, this inserts the GC ref into the over-approximated-stack-roots list, as the Wasm stack logically holds a reference to the object. That reference is cleaned up when we scan the stack during GC and consolidate between what is actually still in use on the Wasm stack vs what is only in the OASR list.However, the OASR list cannot contain duplicates (it is an intrusive linked list in the DRC object header) so if the object was already in the list, then we would not insert it into the list again. But this then causes leaks because
expose_gc_ref_to_wasmtook ownership of the GC reference because the OASR list clean up during GC only decrefs a single time.The solution is to decref in
expose_gc_ref_to_wasmwhen the object is already in the OASR list.Fixes #13037
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Wasmtime GitHub notifications bot (Apr 21 2026 at 18:52):fitzgen requested alexcrichton for a review on PR #13166.
Wasmtime GitHub notifications bot (Apr 21 2026 at 18:52):fitzgen requested wasmtime-core-reviewers for a review on PR #13166.
Wasmtime GitHub notifications bot (Apr 21 2026 at 18:58):alexcrichton submitted PR review.
Wasmtime GitHub notifications bot (Apr 21 2026 at 18:58):alexcrichton has enabled auto merge for PR #13166.
Wasmtime GitHub notifications bot (Apr 21 2026 at 19:05):alexcrichton added PR #13166 Fix DRC leak when passing same object to Wasm multiple times to the merge queue.
Wasmtime GitHub notifications bot (Apr 21 2026 at 19:29):github-merge-queue[bot] removed PR #13166 Fix DRC leak when passing same object to Wasm multiple times from the merge queue.
Wasmtime GitHub notifications bot (Apr 21 2026 at 21:57):github-actions[bot] added the label wasmtime:ref-types on PR #13166.
Wasmtime GitHub notifications bot (Apr 21 2026 at 21:57):github-actions[bot] added the label wasmtime:api on PR #13166.
Wasmtime GitHub notifications bot (Apr 21 2026 at 21:58):github-actions[bot] commented on PR #13166:
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Wasmtime GitHub notifications bot (Apr 22 2026 at 13:17):fitzgen updated PR #13166.
Wasmtime GitHub notifications bot (Apr 22 2026 at 13:17):fitzgen has enabled auto merge for PR #13166.
Wasmtime GitHub notifications bot (Apr 22 2026 at 13:32):fitzgen added PR #13166 Fix DRC leak when passing same object to Wasm multiple times to the merge queue.
Wasmtime GitHub notifications bot (Apr 22 2026 at 13:56):fitzgen merged PR #13166.
Wasmtime GitHub notifications bot (Apr 22 2026 at 13:56):fitzgen removed PR #13166 Fix DRC leak when passing same object to Wasm multiple times from the merge queue.
Last updated: May 03 2026 at 22:13 UTC