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 979b66b300a8e1e471df176cab756444f66fa08f..5340ed064cfd689097468a162b1bbd0d5732289d 100644 (file)
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -135,6 +135,7 @@ libpqrcv_connect(char *conninfo, XLogRecPtr startpoint)
                         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"),