2017-09-19 12:21:24

by Stefan Mätje

Subject: linux-4.14-rc1/arch/x86/include/asm/uaccess.h: Missing include of <linux/sched.h>

Resend with changed subject:

Hi,

there is a change in Linus' mainline kernel for 4.14-rc1
(https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/x86/include/asm/uaccess.h?id=6c51e67b64d169419fb13318035bb442f9176612)
that changes the set_fs() macro into an inline function.

This breaks the build of an out of kernel driver I maintain with this
message:

./arch/x86/include/asm/uaccess.h: In function ‘set_fs’:
./arch/x86/include/asm/uaccess.h:31:9: error: dereferencing pointer to
incomplete type

set_fs() is referencing the "current" pointer which is of type "struct
task_struct" declared in include/linux/sched.h.

Before the change set_fs() was a macro. Because I don't use it it was of
no concern for me. But now the compiler needs to compile the inline
function set_fs() and fails.

Should I add the needed <linux/sched.h> myself in my code or will that
be changed / fixed in the <asm/uaccess.h> header by including the
missing header.

Thanks for any advice.

Best regards,
Stefan Mätje

2017-09-19 13:12:41

by Seraphime Kirkovski

Subject: Re: linux-4.14-rc1/arch/x86/include/asm/uaccess.h: Missing include of <linux/sched.h>

Hi,

> ./arch/x86/include/asm/uaccess.h: In function ‘set_fs’:
> ./arch/x86/include/asm/uaccess.h:31:9: error: dereferencing pointer to
> incomplete type

I can reproduce your problem by including <asm/uaccess.h>, but not with
<linux/uaccess.h>.

#include <asm/uaccess.h>
//#include <linux/uaccess.h> does compile
#include <linux/module.h>


int __init init(void)
{
set_fs(get_fs());
return 0;
}

void __exit finit(void)
{
}

module_init(init);
module_exit(finit);

If my memory is any good, direct inclusion of <asm/uaccess.h> was
deprecated in 4.12 and new code should use <linux/uaccess.h>

Thanks,
Seraphime Kirkovski

2017-09-19 13:57:10

by Stefan Mätje

Subject: Re: linux-4.14-rc1/arch/x86/include/asm/uaccess.h: Missing include of <linux/sched.h>

Hi,

changing the include line to <linux/uaccess.h> solves the problem for me.

Thank you for taking the time to look into this.

Best regards,
Stefan Mätje

Am 19.09.2017 um 15:12 schrieb Seraphime Kirkovski:
> Hi,
>
>> ./arch/x86/include/asm/uaccess.h: In function ‘set_fs’:
>> ./arch/x86/include/asm/uaccess.h:31:9: error: dereferencing pointer to
>> incomplete type
>
> I can reproduce your problem by including <asm/uaccess.h>, but not with
> <linux/uaccess.h>.
>
> #include <asm/uaccess.h>
> //#include <linux/uaccess.h> does compile
> #include <linux/module.h>

My code doesn't use set_fs() but it is only in the header.

> If my memory is any good, direct inclusion of <asm/uaccess.h> was
> deprecated in 4.12 and new code should use <linux/uaccess.h>

I did miss this deprecation.

> Thanks,
> Seraphime Kirkovski
>