Re: [PATCH] futex: futex_find_get_task make credentials check conditional

[Thomas Gleixner <tglx@linutronix.de>]

On Tue, 29 Jun 2010, Darren Hart wrote:
> On 06/29/2010 09:41 AM, Linus Torvalds wrote:
> > 
> > The other thing I'd like to see is to move the whole cred checking up
> > a level. There's no reason to check the credentials in
> > futex_find_get_task() that I can see - why not do it in the caller
> > instead? IOW, I think futex_find_get_task() should just look something
> > like this instead:
> 
> 
> /me beats head on desk, duh. Still, I'm hoping this isn't necessary and we can
> lose the credentials checking entirely.

I did some archaeology in my mail and code archives.

The only hint I found from the early days of the PI futex code is a
mail which mutters something about pid reuse. The euid/uid check
surfaced in the code archive right after that, but to be honest I fail
to see how it should be related. I rather believe that the whole thing
resulted out of being overly paranoid about the PI usage.

Jakub, any idea why this check got there ?

Today I cannot see a real reason to keep that check, it just adds a
restriction for no benefit.

Thanks,

	tglx