2013-05-08 07:42:31

by Dan Carpenter

Subject: [patch] err.h: IS_ERR() can accept __user pointers

Sparse generates a false positive when you pass a __user or __iomem
pointer to the IS_ERR() functions.

drivers/rtc/rtc-ds1286.c:344:36: sparse: incorrect type in argument 1 (different address spaces)
drivers/rtc/rtc-ds1286.c:344:36: expected void const *ptr
drivers/rtc/rtc-ds1286.c:344:36: got unsigned int [noderef] [usertype] <asn:2>*rtcregs

We can silence these by adding a __force here and upgrading to the
latest git release of Sparse.

Signed-off-by: Dan Carpenter <[email protected]>
---
This change has no effect when using current Sparse releases.

diff --git a/include/linux/err.h b/include/linux/err.h
index f2edce2..221fcfb 100644
--- a/include/linux/err.h
+++ b/include/linux/err.h
@@ -24,17 +24,17 @@ static inline void * __must_check ERR_PTR(long error)
return (void *) error;
}

-static inline long __must_check PTR_ERR(const void *ptr)
+static inline long __must_check PTR_ERR(__force const void *ptr)
{
return (long) ptr;
}

-static inline long __must_check IS_ERR(const void *ptr)
+static inline long __must_check IS_ERR(__force const void *ptr)
{
return IS_ERR_VALUE((unsigned long)ptr);
}

-static inline long __must_check IS_ERR_OR_NULL(const void *ptr)
+static inline long __must_check IS_ERR_OR_NULL(__force const void *ptr)
{
return !ptr || IS_ERR_VALUE((unsigned long)ptr);
}
@@ -46,13 +46,13 @@ static inline long __must_check IS_ERR_OR_NULL(const void *ptr)
* Explicitly cast an error-valued pointer to another pointer type in such a
* way as to make it clear that's what's going on.
*/
-static inline void * __must_check ERR_CAST(const void *ptr)
+static inline void * __must_check ERR_CAST(__force const void *ptr)
{
/* cast away the const */
return (void *) ptr;
}

-static inline int __must_check PTR_RET(const void *ptr)
+static inline int __must_check PTR_RET(__force const void *ptr)
{
if (IS_ERR(ptr))
return PTR_ERR(ptr);

2013-05-08 08:39:25

by Christopher Li

Subject: Re: [patch] err.h: IS_ERR() can accept __user pointers

On Wed, May 8, 2013 at 12:42 AM, Dan Carpenter <[email protected]> wrote:
> Sparse generates a false positive when you pass a __user or __iomem
> pointer to the IS_ERR() functions.
>
> drivers/rtc/rtc-ds1286.c:344:36: sparse: incorrect type in argument 1 (different address spaces)
> drivers/rtc/rtc-ds1286.c:344:36: expected void const *ptr
> drivers/rtc/rtc-ds1286.c:344:36: got unsigned int [noderef] [usertype] <asn:2>*rtcregs
>
> We can silence these by adding a __force here and upgrading to the
> latest git release of Sparse.
>
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> This change has no effect when using current Sparse releases.

Acked.

Chris

2013-05-08 22:16:26

by Andrew Morton

Subject: Re: [patch] err.h: IS_ERR() can accept __user pointers

On Wed, 8 May 2013 10:42:22 +0300 Dan Carpenter <[email protected]> wrote:

> Sparse generates a false positive when you pass a __user or __iomem
> pointer to the IS_ERR() functions.
>
> drivers/rtc/rtc-ds1286.c:344:36: sparse: incorrect type in argument 1 (different address spaces)
> drivers/rtc/rtc-ds1286.c:344:36: expected void const *ptr
> drivers/rtc/rtc-ds1286.c:344:36: got unsigned int [noderef] [usertype] <asn:2>*rtcregs
>
> We can silence these by adding a __force here and upgrading to the
> latest git release of Sparse.
>
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> This change has no effect when using current Sparse releases.

You often put really important stuff after the ^--- and I always move
it to before the ^--- :)