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fix(udpserver): data race on a session record's stream cleanup between duplicate SESSION_INITs - #214
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masterking32 merged 1 commit intoNov 2, 2026
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handleSessionInitRequest set record.streamCleanup after findOrCreate had returned the record and released the session store's lock. A client races identical SESSION_INIT queries and resolvers retry them, so several DNS workers handle duplicates of one session init at once and get the same record: they write the field concurrently, and a duplicate that arrives later (a record is reused for SESSION_INIT_REUSE_TTL_SECONDS) writes it while onStreamClosed reads it as the session's streams close. go test -race reports the conflicting writes. Keep the cleanup on the session store, set by New before the server runs, and copy it into each record as findOrCreate creates it, so a record's streamCleanup is never written afterwards. Found with go test -race while running the client's session start against several resolvers. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EE5jVdfYhhc4swGjwfyXGW
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handleSessionInitRequest set record.streamCleanup after findOrCreate had returned the record and released the session store's lock. A client races identical SESSION_INIT queries and resolvers retry them, so several DNS workers handle duplicates of one session init at once and get the same record: they write the field concurrently, and a duplicate that arrives later (a record is reused for SESSION_INIT_REUSE_TTL_SECONDS) writes it while onStreamClosed reads it as the session's streams close. go test -race reports the conflicting writes.
Keep the cleanup on the session store, set by New before the server runs, and copy it into each record as findOrCreate creates it, so a record's streamCleanup is never written afterwards.
Found with go test -race while running the client's session start against several resolvers.
Claude-Session: https://claude.ai/code/session_01EE5jVdfYhhc4swGjwfyXGW