2017-12-09 16:24:28

by Christophe Leroy

[permalink] [raw]
Subject: [PATCH] lib/usercopy: fix sparse errors

CHECK lib/usercopy.c
lib/usercopy.c:26:13: warning: incorrect type in argument 1 (different address spaces)
lib/usercopy.c:26:13: expected void const volatile [noderef] <asn:1>*<noident>
lib/usercopy.c:26:13: got void *to
lib/usercopy.c:27:34: warning: incorrect type in argument 1 (different address spaces)
lib/usercopy.c:27:34: expected void const volatile *p
lib/usercopy.c:27:34: got void const [noderef] <asn:1>*from
lib/usercopy.c:28:38: warning: incorrect type in argument 1 (different address spaces)
lib/usercopy.c:28:38: expected void [noderef] <asn:1>*to
lib/usercopy.c:28:38: got void *to
lib/usercopy.c:28:42: warning: incorrect type in argument 2 (different address spaces)
lib/usercopy.c:28:42: expected void const *from
lib/usercopy.c:28:42: got void const [noderef] <asn:1>*from
lib/usercopy.c:23:15: error: symbol '_copy_to_user' redeclared with different type (originally declared at ./include/linux/uaccess.h:140) - incompatible argument 1 (different address spaces)
CC lib/usercopy.o

Fixes: d597580d37377 ("generic ...copy_..._user primitives")
Signed-off-by: Christophe Leroy <[email protected]>
---
lib/usercopy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/usercopy.c b/lib/usercopy.c
index 15e2e6f..3744b2a 100644
--- a/lib/usercopy.c
+++ b/lib/usercopy.c
@@ -20,7 +20,7 @@ EXPORT_SYMBOL(_copy_from_user);
#endif

#ifndef INLINE_COPY_TO_USER
-unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
+unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
if (likely(access_ok(VERIFY_WRITE, to, n))) {
--
2.2.2


---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus


2017-12-17 17:21:45

by Luc Van Oostenryck

[permalink] [raw]
Subject: Re: [PATCH] lib/usercopy: fix sparse errors

On Sat, Dec 09, 2017 at 05:24:24PM +0100, Christophe Leroy wrote:
> CHECK lib/usercopy.c
> lib/usercopy.c:26:13: warning: incorrect type in argument 1 (different address spaces)
> lib/usercopy.c:26:13: expected void const volatile [noderef] <asn:1>*<noident>
> lib/usercopy.c:26:13: got void *to
> lib/usercopy.c:27:34: warning: incorrect type in argument 1 (different address spaces)
> lib/usercopy.c:27:34: expected void const volatile *p
> lib/usercopy.c:27:34: got void const [noderef] <asn:1>*from
> lib/usercopy.c:28:38: warning: incorrect type in argument 1 (different address spaces)
> lib/usercopy.c:28:38: expected void [noderef] <asn:1>*to
> lib/usercopy.c:28:38: got void *to
> lib/usercopy.c:28:42: warning: incorrect type in argument 2 (different address spaces)
> lib/usercopy.c:28:42: expected void const *from
> lib/usercopy.c:28:42: got void const [noderef] <asn:1>*from
> lib/usercopy.c:23:15: error: symbol '_copy_to_user' redeclared with different type (originally declared at ./include/linux/uaccess.h:140) - incompatible argument 1 (different address spaces)
> CC lib/usercopy.o
>
> Fixes: d597580d37377 ("generic ...copy_..._user primitives")
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> lib/usercopy.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/usercopy.c b/lib/usercopy.c
> index 15e2e6f..3744b2a 100644
> --- a/lib/usercopy.c
> +++ b/lib/usercopy.c
> @@ -20,7 +20,7 @@ EXPORT_SYMBOL(_copy_from_user);
> #endif
>
> #ifndef INLINE_COPY_TO_USER
> -unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
> +unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
> {
> might_fault();
> if (likely(access_ok(VERIFY_WRITE, to, n))) {
> --

Hi,

The change is good.
The commit message would better simply describe the problem instead
of describing the symptom. For example, something like:
The function _copy_to_user() is used to copy to address space.
As such, the destination pointer should be annotated with
'__user'.
However, the function has the annotation wrongly, on the
source instead of the destination (copy & paste error?).
Fix this by moving the __user annotation to the correct
argument.


-- Luc Van Oostenryck

2017-12-17 17:31:27

by Al Viro

[permalink] [raw]
Subject: Re: [PATCH] lib/usercopy: fix sparse errors

> The change is good.
> The commit message would better simply describe the problem instead
> of describing the symptom. For example, something like:
> The function _copy_to_user() is used to copy to address space.
> As such, the destination pointer should be annotated with
> '__user'.
> However, the function has the annotation wrongly, on the
> source instead of the destination (copy & paste error?).
> Fix this by moving the __user annotation to the correct
> argument.

FWIW, I've committed it with

Fix misannotated out-of-line _copy_to_user()

Destination is a kernel pointer and source - a userland one
is _copy_from_user(); _copy_to_user() is the other way round.