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Destroy MPSC queue elements before releasing nodes - #3620
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chenBright merged 1 commit intoOct 18, 2026
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🟢 Approval recommended
The focused cleanup fix covers both removal paths, includes regression tests, and has no unresolved findings.
No open issues 🎉
What changed in this PR
This PR fixes resource leaks in MPSCQueue by destroying stored values before releasing their nodes.
Changes:
- Add element destruction to the shared dequeue cleanup path.
- Add regression tests for dequeued elements and elements left pending at queue destruction.
| File | Description |
|---|---|
| test/mpsc_queue_unittest.cc | Adds lifetime-tracking regression tests for both cleanup paths. |
| src/butil/containers/mpsc_queue.h | Destroys the stored value before freeing the node. |
Review effort: Balanced
Sherlock0203
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Oct 19, 2026
Bring the apache master line up to f0239d7 into this branch in a single merge, replacing the two stacked merges with master@36c2d12e and the macOS fix only. Everything the branch needs from that line is included: the data-format negotiation (apache#3507), the IPC_V2 data path (apache#3573), the macOS OpenSSL 4.0 build fix (apache#3616: X509 accessors return const pointers in the current macos-26-arm64 runner image, fixed with auto*), and the newer fixes, notably the null-termination of the peer shm_name in HelloMessage::Deserialize (apache#3605), the MPSC queue node release ordering (apache#3620) and the MultiFlatMap bucket-head erasure fix (apache#3617). Those master changes were built on the timerfd-era close path, which this branch had replaced with the bthread timer facade, generation-checked pool teardown and the cleanup worker, so both sides evolved the same ubshm core after 9334389. Resolution: - Close/clear core (UbrTrxClose, UbrTrxCloseCallback, UbrClearResourceCheck, ClearTrxResource, UbrPassiveClearTrx, UbrTrxCloseCheck) keeps this branch's versions. Master's extra start_time/op parameters were unused, and UbrCloseType only chose between DeleteTimerSafe and DeleteTimer, which the facade subsumes: UbrTimerDelAndWait degrades to the non-blocking delete inside a callback. The unused UbrCloseType enum is therefore dropped. - Master's format-aware initialization is kept: UbrServerTrxInit keeps the UbrDataFormat parameter and the Initialize*LegacyFormat split, UbrAllocateServerShm/UbrMapRemoteShm(UbrMapRemoteShmAddTimer) keep passing it, and ApplyAndMapLocalShm no longer presets the rx capacity (InitializeClientLocalLegacyFormat owns that now). All IPC_V2 ring code and the negotiation handshake are master's, unchanged, with master-side UNLIKELY/LIKELY converted to the module's BAIDU_* macros. - This branch's fixes that master lacked merge on top: the poller re-ADD refresh, butil::atomic for the poller-group flag, the lazy bthread timers replacing TimerInit, and the cleanup-worker changes (leaked queue, start retry instead of the terminal latch). - test/brpc_ubring_unittest.cpp: master's IPC_V2 assertions on the removed timer_fd/hb_timer_fd fields check the unarmed close_timer/hb_timer slots instead, and the UbrCleanupWorkerTest that PR LinQuickDev#74's squash dropped is restored alongside master's apache#3605 hardening of the full_shm_name test. Both sides' suites run. Tested: the close/cleanup/IPC_V2 resolution was verified on the equivalent tree before apache#3605 came in -- cmake WITH_UBRING=ON build, 31/31 unit tests, the same under ASAN (detect_leaks=0), and an example/ubring_performance e2e over the IPC backend (negotiated IPC_V2 path at ~148k QPS, clean teardowns, server kill -9 handled). The new master commits are additive to that resolution; cmake --build build --target brpc_ubring_unittest and ./build/test/brpc_ubring_unittest pass on this exact tree as well.
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What problem does this PR solve?
Issue Number: resolve
Problem Summary:
MPSCQueuestores each queued value inManualConstructor<T>, whosedestructor does not automatically destroy the contained object.
When a node is dequeued or discarded during queue destruction, the node is
returned to its allocator without destroying its
Tvalue. For non-trivialtypes, this skips destructors and can leak resources held by queued elements.
What is changed and the side effects?
Changed:
allocator.
and elements destroyed after dequeue.
Side effects:
Performance effects:
Breaking backward compatibility:
Check List: