Re: [RFC] syscalls, x86: Add __NR_kcmp syscall

[H. Peter Anvin]

On 01/20/2012 08:29 AM, Cyrill Gorcunov wrote:
> We've had kind of emergency pool before which were used in such cases.
> These legitime cases can happen not that frequently, so I guess -- can
> we use it again?
>
> 	if (cookies[i][j])
> 		continue;
> 	else
> 		cookies[i][j] = some-value;
>
> One wont know which exactly values we were using.

I would not worry about get_random_bytes() returning nothing... if so, a 
lot of other places in the kernel would be broken.

> > The other thing is that for the multiplicative cookie you should OR in
> > the value (~(~0UL>>  1) | 1) in order to make sure that the value is (a)
> > large and (b) odd.
>
> I see, i'll update (at first, I occasionally translated odd as 'even' which
> made me really scratching the head, until I realized it's 'odd'! :)
>
> 	Cyrill

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