linux-kernel - [PATCH 2/3] xtensa: fix type conversion in __get_user

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Date:   Fri, 22 May 2020 14:41:52 -0700
From:   Max Filippov <jcmvbkbc@...il.com>
To:     linux-xtensa@...ux-xtensa.org
Cc:     Chris Zankel <chris@...kel.net>, Arnd Bergmann <arnd@...db.de>,
        Al Viro <viro@...iv.linux.org.uk>,
        linux-kernel@...r.kernel.org, Max Filippov <jcmvbkbc@...il.com>
Subject: [PATCH 2/3] xtensa: fix type conversion in __get_user_size

8-byte access in __get_user_size converts pointer to temporary variable
to the type of original user pointer and then dereferences it, resulting
in the following sparse warning:

  sparse: warning: dereference of noderef expression

Instead dereference the original user pointer under the __typeof__ and
add indirection outside.

Signed-off-by: Max Filippov <jcmvbkbc@...il.com>
---
 arch/xtensa/include/asm/uaccess.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h
index 754a7c96b9da..445bb4cf3c28 100644
--- a/arch/xtensa/include/asm/uaccess.h
+++ b/arch/xtensa/include/asm/uaccess.h
@@ -204,7 +204,7 @@ do {									\
 			retval = -EFAULT;				\
 			(x) = 0;					\
 		} else {						\
-			(x) = *(__force __typeof__((ptr)))&__x;		\
+			(x) = *(__force __typeof__(*(ptr)) *)&__x;	\
 		}							\
 		break;							\
 	}								\
-- 
2.20.1