btc(v36): complete livelock mirror — hold tracker lock across IO-thread share mutations - #117
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…ad share mutations Mirrors LTC f445db8 onto the BTC twin. PR #97 landed only the watchdog half; the lock-yield half was inert (test-then-release). Two IO-thread sites read/mutated m_tracker.chain racing the compute-thread clean_tracker() exclusive prune (drop_tails), freeing chain nodes mid-access -> SIGSEGV (kr1z1s LTC/DGB shape): - processing_shares_phase2(): held the try_to_lock only to TEST availability, released it, then ran m_tracker.add() lock-free. The unique_lock is now held across the whole mutation body and released just before the async run_think() trigger. BTC-only backpressure cap (MAX_PENDING_ADDS) preserved. - notify_local_share(): bare m_tracker.chain.contains() in the early-return ran outside the lock. Moved under the existing try_to_lock guard (owns_lock() && contains()); on contention the inline verify is skipped and run_think() scores the share next cycle. BTC-only (src/impl/btc/node.cpp). Same non-blocking IO-thread contract (busy -> defer/queue, never block).
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Completes the BTC twin of the contabo run_think() livelock / kr1z1s SIGSEGV fix.
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LTC fix has landed on master:
f445db8eltc/node: hold tracker lock across chain access in IO-thread share paths2f9d3e1aFix event-loop freeze: try_to_lock in IO-thread tracker accessesPR #97 (
ee906e8a) landed only the watchdog half of the BTC mirror; the lock-yield half was inert (test-then-release). This PR mirrorsf445db8e1:1 ontosrc/impl/btc/node.cpp.Changes (BTC-only)
try_to_lockonly to TEST availability, released it, then ranm_tracker.add()lock-free on the "think() isnt running" assumption. The compute-threadclean_tracker()prune could grab the lock the instant phase2 released it and free chain nodes mid-mutation → SIGSEGV. Theunique_lockis now held across the whole mutation body and released (lock.unlock()) immediately before the asyncrun_think()trigger. BTC-only backpressure cap (MAX_PENDING_ADDS) preserved inside the!owns_lock()branch.m_tracker.chain.contains()in the early-return ran outside the lock. Moved under the existingtry_to_lockguard (owns_lock() && contains()); on contention the inline verify is skipped andrun_think()scores the share next cycle.Verification
cmake --build build --target c2pool-btc -j16→ BUILD_EXIT=0 (warnings only).e8abf28dGPG-signed.Merge operator-gated.