diff --git a/src/backend/utils/adt/nabstime.c b/src/backend/utils/adt/nabstime.c
index fae97135db..af430f2d2c 100644
--- a/src/backend/utils/adt/nabstime.c
+++ b/src/backend/utils/adt/nabstime.c
@@ -106,6 +106,9 @@ abstime2tm(AbsoluteTime _time, int *tzp, struct pg_tm *tm, char **tzn)
 	else
 		tx = pg_gmtime(&time);
 
+	if (tx == NULL)
+		elog(ERROR, "could not convert abstime to timestamp: %m");
+
 	tm->tm_year = tx->tm_year + 1900;
 	tm->tm_mon = tx->tm_mon + 1;
 	tm->tm_mday = tx->tm_mday;
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 1d75caebe1..4dac27e849 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -1988,6 +1988,9 @@ GetEpochTime(struct pg_tm *tm)
 
 	t0 = pg_gmtime(&epoch);
 
+	if (t0 == NULL)
+		elog(ERROR, "could not convert epoch to timestamp: %m");
+
 	tm->tm_year = t0->tm_year;
 	tm->tm_mon = t0->tm_mon;
 	tm->tm_mday = t0->tm_mday;
diff --git a/src/timezone/localtime.c b/src/timezone/localtime.c
index 31b06b037f..a2260e590d 100644
--- a/src/timezone/localtime.c
+++ b/src/timezone/localtime.c
@@ -1328,13 +1328,14 @@ gmtsub(pg_time_t const *timep, int32 offset, struct pg_tm *tmp)
 	struct pg_tm *result;
 
 	/* GMT timezone state data is kept here */
-	static struct state gmtmem;
-	static bool gmt_is_set = false;
-#define gmtptr		(&gmtmem)
+	static struct state *gmtptr = NULL;
 
-	if (!gmt_is_set)
+	if (gmtptr == NULL)
 	{
-		gmt_is_set = true;
+		/* Allocate on first use */
+		gmtptr = (struct state *) malloc(sizeof(struct state));
+		if (gmtptr == NULL)
+			return NULL;		/* errno should be set by malloc */
 		gmtload(gmtptr);
 	}
 	result = timesub(timep, offset, gmtptr, tmp);