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 96f31c4c55b0cec5fbcba9d81f915fb4ef8ffa1a..88d27c7690e8ab170faaf84e32c93e01f3ba4eae 100644 (file)
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -152,6 +152,7 @@ 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"),