Index: uspace/lib/c/generic/io/vprintf.c
===================================================================
--- uspace/lib/c/generic/io/vprintf.c	(revision 61bfc370dac47cccde963c4beaae3f6a0a364c54)
+++ uspace/lib/c/generic/io/vprintf.c	(revision e08a73395d806318f3ac81da5e42459be2c60d2c)
@@ -37,9 +37,9 @@
 #include <unistd.h>
 #include <io/printf_core.h>
-#include <futex.h>
+#include <fibril_synch.h>
 #include <async.h>
 #include <str.h>
 
-static atomic_t printf_futex = FUTEX_INITIALIZER;
+static FIBRIL_MUTEX_INITIALIZE(printf_mutex);
 
 static int vprintf_str_write(const char *str, size_t size, void *stream)
@@ -85,16 +85,9 @@
 	 * Prevent other threads to execute printf_core()
 	 */
-	futex_down(&printf_futex);
-	
-	/*
-	 * Prevent other fibrils of the same thread
-	 * to execute printf_core()
-	 */
-	async_serialize_start();
+	fibril_mutex_lock(&printf_mutex);
 	
 	int ret = printf_core(fmt, &ps, ap);
 	
-	async_serialize_end();
-	futex_up(&printf_futex);
+	fibril_mutex_unlock(&printf_mutex);
 	
 	return ret;