Hi, While going through the code of the slot sync worker, I found that in functions ReplSlotSyncWorkerMain and pg_sync_replication_slots the variable app_name.data is being used after it is freed.
We can get logs as following:
2025-09-02 12:26:48.520 IST [3908359] ERROR: synchronization worker
"" could not connect to the primary server: connection to server at
"localhost" (127.0.0.1), port 5432 failed: Connection refused
Is the server running on that host and accepting TCP/IP connections?
I have moved the pfree(app_data.name) after its usage.
This change was introduced in PG_18.
The patch applies in the HEAD and REL_18_STABLE branches.
Thanks,
Shlok Kyal
v1-0001-Fix-use-of-variable-after-pfree.patch
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