diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 1f6069e4dc67..5e6557289c34 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -199,7 +199,7 @@ m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
 		ref_cnt = (u_int *)uma_find_refcnt(zone_clust,
 		    mb->m_ext.ext_buf);
 	else if (type == EXT_EXTREF)
-		ref_cnt = mb->m_ext.ref_cnt;
+		ref_cnt = __DEVOLATILE(u_int *, mb->m_ext.ref_cnt);
 	mb->m_ext.ref_cnt = (ref_cnt == NULL) ?
 	    malloc(sizeof(u_int), M_MBUF, M_NOWAIT) : (u_int *)ref_cnt;
 	if (mb->m_ext.ref_cnt != NULL) {
@@ -234,12 +234,9 @@ mb_free_ext(struct mbuf *m)
 	 * This is tricky.  We need to make sure to decrement the
 	 * refcount in a safe way but to also clean up if we're the
 	 * last reference.  This method seems to do it without race.
-	 * The volatile cast is required to emit the proper load 
-	 * instructions. Otherwise gcc will optimize the read outside
-	 * of the while loop.
 	 */
 	while (dofree == 0) {
-		cnt = *(volatile u_int *)(m->m_ext.ref_cnt);
+		cnt = *(m->m_ext.ref_cnt);
 		if (atomic_cmpset_int(m->m_ext.ref_cnt, cnt, cnt - 1)) {
 			if (cnt == 1)
 				dofree = 1;
@@ -262,7 +259,8 @@ mb_free_ext(struct mbuf *m)
 			    m->m_ext.ext_args);
 			if (m->m_ext.ext_type != EXT_EXTREF) {
 				if (m->m_ext.ref_cnt != NULL)
-					free(m->m_ext.ref_cnt, M_MBUF);
+					free(__DEVOLATILE(u_int *,
+					    m->m_ext.ref_cnt), M_MBUF);
 				m->m_ext.ref_cnt = NULL;
 			}
 			m->m_ext.ext_buf = NULL;
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 1621fa716252..07039163f097 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -122,7 +122,7 @@ struct m_ext {
 		    (void *, void *);
 	void	*ext_args;		/* optional argument pointer */
 	u_int	ext_size;		/* size of buffer, for ext_free */
-	u_int	*ref_cnt;		/* pointer to ref count info */
+	volatile u_int *ref_cnt;	/* pointer to ref count info */
 	int	ext_type;		/* type of external storage */
 };