Index: uspace/lib/c/generic/futex.c
===================================================================
--- uspace/lib/c/generic/futex.c	(revision a74d0ad855d5ae331fcd2023dcc2b0281b01e5e9)
+++ uspace/lib/c/generic/futex.c	(revision c501bc4364ecfead182958bc0b7c059b09e5cf4e)
@@ -35,4 +35,5 @@
 #include <futex.h>
 #include <atomic.h>
+#include <libarch/barrier.h>
 #include <libc.h>
 #include <sys/types.h>
@@ -59,5 +60,10 @@
 int futex_trydown(futex_t *futex)
 {
-	return cas(futex, 1, 0);
+	int rc;
+
+	rc = cas(futex, 1, 0);
+	CS_ENTER_BARRIER();
+
+	return rc;
 }
 
@@ -73,5 +79,9 @@
 int futex_down(futex_t *futex)
 {
-	if ((atomic_signed_t) atomic_predec(futex) < 0)
+	atomic_signed_t nv;
+
+	nv = (atomic_signed_t) atomic_predec(futex);
+	CS_ENTER_BARRIER();
+	if (nv < 0)
 		return __SYSCALL1(SYS_FUTEX_SLEEP, (sysarg_t) &futex->count);
 	
@@ -89,4 +99,6 @@
 int futex_up(futex_t *futex)
 {
+	CS_LEAVE_BARRIER();
+
 	if ((atomic_signed_t) atomic_postinc(futex) < 0)
 		return __SYSCALL1(SYS_FUTEX_WAKEUP, (sysarg_t) &futex->count);