Re: [syzbot] [virtualization?] KMSAN: uninit-value in virtqueue_add (4)

[Tetsuo Handa]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index cc6b8e087192..f13bba3a9dab 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -58,7 +58,16 @@ static inline void clear_page(void *page)
 			   : "cc", "memory", "rax", "rcx");
 }
 
+#ifdef CONFIG_KMSAN
+/* Use of non-instrumented assembly version confuses KMSAN. */
+void *memcpy(void *to, const void *from, __kernel_size_t len);
+static inline void copy_page(void *to, void *from)
+{
+	memcpy(to, from, PAGE_SIZE);
+}
+#else
 void copy_page(void *to, void *from);
+#endif
 
 #ifdef CONFIG_X86_5LEVEL
 /*
-- 
2.34.1