Index: nspr/pr/src/misc/prnetdb.c
--- nspr/pr/src/misc/prnetdb.c.orig
+++ nspr/pr/src/misc/prnetdb.c
@@ -2315,7 +2315,9 @@ 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;
