diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 771a84e3077da430907c9e1e578f3911419b5720..9f44ed8f00239992e1648a835afd77c297b54117 100644
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -199,6 +199,11 @@ static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
 static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
 					    int orig_val)
 {
+	/*
+	 * other observers should notice all modifications
+	 * in the freezing period.
+	 */
+	smp_mb();
 	atomic_set(&grp->refcount, orig_val);
 	preempt_enable();
 }