diff --git a/src/tools/acountry.c b/src/tools/acountry.c
index 924fab47..85419be4 100644
--- a/src/tools/acountry.c
+++ b/src/tools/acountry.c
@@ -229,6 +229,8 @@ static void wait_ares(ares_channel channel)
       if (nfds == 0)
         break;
       tvp = ares_timeout(channel, NULL, &tv);
+      if (tvp == NULL)
+        break;
       nfds = select(nfds, &read_fds, &write_fds, NULL, tvp);
       if (nfds < 0)
         continue;
diff --git a/src/tools/adig.c b/src/tools/adig.c
index 28d55ac3..b867be6a 100644
--- a/src/tools/adig.c
+++ b/src/tools/adig.c
@@ -375,6 +375,8 @@ int main(int argc, char **argv)
       if (nfds == 0)
         break;
       tvp = ares_timeout(channel, NULL, &tv);
+      if (tvp == NULL)
+        break;
       count = select(nfds, &read_fds, &write_fds, NULL, tvp);
       if (count < 0 && (status = SOCKERRNO) != EINVAL)
         {
diff --git a/src/tools/ahost.c b/src/tools/ahost.c
index f8a39eb4..2924e5d5 100644
--- a/src/tools/ahost.c
+++ b/src/tools/ahost.c
@@ -167,6 +167,8 @@ int main(int argc, char **argv)
       if (nfds == 0)
         break;
       tvp = ares_timeout(channel, NULL, &tv);
+      if (tvp == NULL)
+        break;
       res = select(nfds, &read_fds, &write_fds, NULL, tvp);
       if (-1 == res)
         break;