diff --git a/libraries/liblber/io.c b/libraries/liblber/io.c
index 58f6b64911..7154d3480c 100644
--- a/libraries/liblber/io.c
+++ b/libraries/liblber/io.c
@@ -221,7 +221,7 @@ ber_flush( Sockbuf *sb, BerElement *ber, int freeit )
 	assert( sb != NULL );
 	assert( ber != NULL );
 
-	assert( SOCKBUF_VALID( ber ) );
+	assert( SOCKBUF_VALID( sb ) );
 	assert( BER_VALID( ber ) );
 
 	if ( ber->ber_rwptr == NULL ) {