Index: nspr/pr/src/misc/prnetdb.c
--- nspr/pr/src/misc/prnetdb.c.orig
+++ nspr/pr/src/misc/prnetdb.c
@@ -2011,7 +2011,9 @@ PR_GetAddrInfoByName(const char* hostname, PRUint16 af
      */
     hints.ai_socktype = SOCK_STREAM;
 
+    LOCK_DNS();
     rv = GETADDRINFO(hostname, NULL, &hints, &res);
+    UNLOCK_DNS();
 #  ifdef AI_ADDRCONFIG
     if (rv == EAI_BADFLAGS && (hints.ai_flags & AI_ADDRCONFIG)) {
       hints.ai_flags &= ~AI_ADDRCONFIG;
