diff --git a/library/debug.c b/library/debug.c
index a032478..a9cd814 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -86,7 +86,7 @@
     char str[DEBUG_BUF_SIZE];
     int ret;
 
-    if( ssl->conf == NULL || ssl->conf->f_dbg == NULL || level > debug_threshold )
+    if( NULL == ssl || NULL == ssl->conf || NULL == ssl->conf->f_dbg || level > debug_threshold )
         return;
 
     va_start( argp, format );