arch/x86/include/asm/uaccess_64.h |  2 +-
 arch/x86/lib/usercopy_64.c        | 15 +++++++--------
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 12a26b979bf1..f2f9b39b274a 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -231,6 +231,6 @@ __copy_from_user_inatomic_nocache(void *dst, const void __user *src,
 }
 
 unsigned long
-copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest);
+copy_user_handle_tail(char *to, char *from, unsigned len);
 
 #endif /* _ASM_X86_UACCESS_64_H */
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index c905e89e19fe..1f33b3d1fd68 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -69,21 +69,20 @@ EXPORT_SYMBOL(copy_in_user);
  * it is not necessary to optimize tail handling.
  */
 __visible unsigned long
-copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
+copy_user_handle_tail(char *to, char *from, unsigned len)
 {
-	char c;
-	unsigned zero_len;
-
 	for (; len; --len, to++) {
+		char c;
+
 		if (__get_user_nocheck(c, from++, sizeof(char)))
 			break;
 		if (__put_user_nocheck(c, to, sizeof(char)))
 			break;
 	}
-
-	for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
-		if (__put_user_nocheck(c, to++, sizeof(char)))
-			break;
 	clac();
+
+	/* If the destination is a kernel buffer, we always clear the end */
+	if ((unsigned long)to >= TASK_SIZE_MAX)
+		memset(to, 0, len);
 	return len;
 }