RE: [RFC PATCH 0/2] init: make sure syscall arguments are marked__user where needed

[H Hartley Sweeten]

In Friday, April 20, 2012 4:01 PM, Andrew Morton wrote:
> On Mon, 16 Apr 2012 17:33:23 -0700 H Hartley Sweeten wrote:
>
>> When using syscall routines in the kernel, some of the arguments
>> should be user pointers but are missing the __user markup. This
>> produces a number of sparse warnings of the format:    
>>   
>> warning: incorrect type in argument 1 (different address spaces)
>>    expected char [noderef] <asn:1>*dev_name
>>    got char *name 
>> 
>> Wrap the syscall routines in the private do_mounts.h header so that
>> the appropriate __user markups are added for the init mount code.
>
> This makes rather a mess of do_mounts.c for pretty marginal benefit.

Well... That's why it was a RFC... ;-)

> Can we just make "make C=1" skip that file or something?

What about putting something like this at the top of the files:


/*
 * Many of the syscalls used in this file expect some of the arguments
 * to be __user pointers not __kernel pointers.  To limit the sparse
 * noise, turn off sparse checking for this file.
 */
#ifdef __CHECKER__
#undef __CHECKER__
#warning "Sparse checking disabled for this file"
#endif


Maybe without the warning if it doesn't seem necessary.

This keeps <linux/compiler.h> from defining the __attribute__* checks.

Regards,
Hartley

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