[SharovBot] db/state: fix DATA RACE between Aggregator.Close and MergeLoop goroutine - #22227
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…eLoop goroutine The background MergeLoop goroutine called a.wg.Add(1) inside MergeLoop itself, but the spawning goroutine in backend.go could race with Close() calling a.wg.Wait(): if Close() observed the WaitGroup counter at zero before the goroutine executed wg.Add(1), Wait() returned early and Close proceeded to write fields (ctxCancel = nil) concurrently with MergeLoop starting up. The race detector reported: WARNING: DATA RACE Write at ... (*Aggregator).Close() aggregator.go:630 Previous read at ... (*Aggregator).MergeLoop() aggregator.go:1228 Fix: add StartMergeLoopBackground to Aggregator (and the TemporalDebugDB interface) which calls wg.Add(1) synchronously before launching the goroutine. This guarantees the counter is non-zero before Close/wg.Wait can be called, eliminating the race. Verified: go test -race -count=3 -run TestImportClosesChaindataOnInitError ./cmd/utils/app/... passes cleanly. Co-authored-by: Giulio Rebuffo <giulio.rebuffo@gmail.com>
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yperbasis
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July 4, 2026 03:48
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fixed by #22203 |
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[SharovBot]
Problem
The CI job
race-tests / tests-linux (ubuntu-latest, other, parallel)on commitbc4670467failed with:Root cause: The background merge goroutine spawned in
backend.gocalleda.wg.Add(1)insideMergeLoop(), after the goroutine was scheduled. A concurrentClose()could observe a zero WaitGroup counter, return fromwg.Wait()immediately, and then write to struct fields (e.g.ctxCancel = nil) concurrently with the goroutine'swg.Add(1)/ mergeLoop startup — a classic wg.Add/wg.Wait race.Fix
Added
StartMergeLoopBackground(ctx, onErr)toAggregator(and theTemporalDebugDBinterface) which callswg.Add(1)synchronously before spawning the goroutine. This guarantees the counter is non-zero before anyClose()/wg.Wait()can execute.backend.gonow usesStartMergeLoopBackgroundinstead of a manual goroutine wrappingMergeLoop.Verification
No DATA RACE warnings. 3/3 passes.
Fixes: https://github.com/erigontech/erigon/actions/runs/28674562917/job/85045122311