Fix use of free in walsender error handling after a sysid mismatch.

Found via valgrind. The bug exists since the introduction of the walsender,
so backpatch to 9.0.

Andres Freund

diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 6bc0aa1c12cdd53a14ce045ae2614dceddccc2bf..1cb2c6e524d2b17d23266275ffb4fa529f614c10 100644 (file)
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -151,6 +151,7 @@ libpqrcv_identify_system(TimeLineID *primary_tli)
             GetSystemIdentifier());
    if (strcmp(primary_sysid, standby_sysid) != 0)
    {
+       primary_sysid = pstrdup(primary_sysid);
        PQclear(res);
        ereport(ERROR,
                (errmsg("database system identifier differs between the primary and standby"),