diff --git a/logging.c b/logging.c
index 7d9dbb8..aee6940 100644
--- a/logging.c
+++ b/logging.c
@@ -132,14 +132,16 @@ void LOG_Message(LOG_Severity severity,
   char buf[2048];
   va_list other_args;
   time_t t;
-  struct tm stm;
+  struct tm *tm;
 
   if (!system_log && file_log) {
     /* Don't clutter up syslog with timestamps and internal debugging info */
     time(&t);
-    stm = *gmtime(&t);
-    strftime(buf, sizeof(buf), "%Y-%m-%dT%H:%M:%SZ", &stm);
-    fprintf(file_log, "%s ", buf);
+    tm = gmtime(&t);
+    if (tm) {
+      strftime(buf, sizeof (buf), "%Y-%m-%dT%H:%M:%SZ", tm);
+      fprintf(file_log, "%s ", buf);
+    }
 #if DEBUG > 0
     if (debug_level >= DEBUG_LEVEL_PRINT_FUNCTION)
       fprintf(file_log, "%s:%d:(%s) ", filename, line_number, function_name);
diff --git a/reference.c b/reference.c
index dff7ab9..dbc40e7 100644
--- a/reference.c
+++ b/reference.c
@@ -528,7 +528,7 @@ maybe_log_offset(double offset, time_t now)
   double abs_offset;
   FILE *p;
   char buffer[BUFLEN], host[BUFLEN];
-  struct tm stm;
+  struct tm *tm;
 
   abs_offset = fabs(offset);
 
@@ -547,9 +547,14 @@ maybe_log_offset(double offset, time_t now)
       }
       fprintf(p, "Subject: chronyd reports change to system clock on node [%s]\n", host);
       fputs("\n", p);
-      stm = *localtime(&now);
-      strftime(buffer, sizeof(buffer), "On %A, %d %B %Y\n  with the system clock reading %H:%M:%S (%Z)", &stm);
-      fputs(buffer, p);
+
+      tm = localtime(&now);
+      if (tm) {
+        strftime(buffer, sizeof (buffer),
+                 "On %A, %d %B %Y\n  with the system clock reading %H:%M:%S (%Z)", tm);
+        fputs(buffer, p);
+      }
+
       /* If offset < 0 the local clock is slow, so we are applying a
          positive change to it to bring it into line, hence the
          negation of 'offset' in the next statement (and earlier) */
diff --git a/rtc_linux.c b/rtc_linux.c
index 89855c2..d4d9bd0 100644
--- a/rtc_linux.c
+++ b/rtc_linux.c
@@ -352,7 +352,7 @@ rtc_from_t(const time_t *t)
 
 static time_t
 t_from_rtc(struct tm *stm) {
-  struct tm temp1, temp2;
+  struct tm temp1, temp2, *tm;
   long diff;
   time_t t1, t2;
 
@@ -360,12 +360,14 @@ t_from_rtc(struct tm *stm) {
   temp1.tm_isdst = 0;
   
   t1 = mktime(&temp1);
-  if (rtc_on_utc) {
-    temp2 = *gmtime(&t1);
-  } else {
-    temp2 = *localtime(&t1);
+
+  tm = rtc_on_utc ? gmtime(&t1) : localtime(&t1);
+  if (!tm) {
+    DEBUG_LOG("gmtime()/localtime() failed");
+    return -1;
   }
-  
+
+  temp2 = *tm;
   temp2.tm_isdst = 0;
   t2 = mktime(&temp2);
   diff = t2 - t1;