Re: [RFC][PATCH] KGDB: remove kgdb-own fault handling

[Jason Wessel <jason.wessel@windriver.com>]

Linus Torvalds wrote:
> On Fri, 8 Feb 2008, Jan Kiszka wrote:
>   
>> Well, let's try it this way: Find below a patch against kgdb.git that
>> removes the special fault handling (this wouldn't be the first feature I
>> recently removed from kgdb :->). Light testing revealed no obvious
>> problems yet.
>>     
>
> That is indeed horrible code. No way will I merge anything that has things 
> like that even in it's *history* (ie somebody needs to re-generate the 
> tree without code like that - some things should not be allowed to exist).
>
>   

I concur.  I will collapse the entire kgdb tree back to the original few
patches which can be bisected.

> That said, while just using "probe_kernel_addr()" is certainly much 
> better, it's still really inefficient. If you actually want to do a "safe 
> memory copy", then the right way to do that is basically to do
>
> 	pagefault_disable();
> 	leftover = __copy_from_user_inatomic(dst, src, count);
> 	pagefault_enable();
>
> 	if (leftover)
> 		handle_the_fact_that_the_copy_didnt_complete();
>
>   

Duly Noted.  Further cleanups are in progress.


Thanks,
Jason.