From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 9 Sep 2016 23:16:58 +0000 (-0400)
Subject: blackfin: fix copy_from_user()
X-Git-Tag: v4.8-rc7~23^2~4
X-Git-Url: https://git.kernel.dk/?p=linux-2.6-block.git;a=commitdiff_plain;h=8f035983dd826d7e04f67b28acf8e2f08c347e41

blackfin: fix copy_from_user()

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/arch/blackfin/include/asm/uaccess.h b/arch/blackfin/include/asm/uaccess.h
index 12f5d6851bbc..0a2a70096d8b 100644
--- a/arch/blackfin/include/asm/uaccess.h
+++ b/arch/blackfin/include/asm/uaccess.h
@@ -171,11 +171,12 @@ static inline int bad_user_access_length(void)
 static inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (access_ok(VERIFY_READ, from, n))
+	if (likely(access_ok(VERIFY_READ, from, n))) {
 		memcpy(to, (const void __force *)from, n);
-	else
-		return n;
-	return 0;
+		return 0;
+	}
+	memset(to, 0, n);
+	return n;
 }
 
 static inline unsigned long __must_check