diff --git a/arch/loongarch/include/asm/vdso/processor.h b/arch/loongarch/include/asm/vdso/processor.h
index ef5770b343a01eadaa3be14705f8be4e30e5d7cd..fa3d08bbde94ad4c96efd7fb4bd4b480d707d6b2 100644
--- a/arch/loongarch/include/asm/vdso/processor.h
+++ b/arch/loongarch/include/asm/vdso/processor.h
@@ -7,7 +7,16 @@
 
 #ifndef __ASSEMBLY__
 
-#define cpu_relax()	barrier()
+/*
+ * Loongson-3's SFB (Store-Fill-Buffer) may buffer writes indefinitely when a
+ * tight read loop is executed, because reads take priority over writes & the
+ * hardware (incorrectly) doesn't ensure that writes will eventually occur.
+ *
+ * Since spin loops of any kind should have a cpu_relax() in them, force an SFB
+ * flush from cpu_relax() such that any pending writes will become visible as
+ * expected.
+ */
+#define cpu_relax()	smp_mb()
 
 #endif /* __ASSEMBLY__ */