Re: Perform mmap and poll on PUD character devices

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sun, Sep 11, 2011 at 11:42:33PM +0200, Jean-Yves Migeon wrote:
> On 11.09.2011 21:07, Thor Lancelot Simon wrote:
> > Similarly, I am not sure I believe the security justification, mostly
> > because I don't really see why I should believe that the very complex
> > memory management code involved in providing the split kernel/user
> > memory-mapped device driver interface this seems to require is less
> > likely to have security-critical bugs than a comparatively simple
> > addition of in-kernel support for a few different virtual disk layouts
> > than the ones we already have code for.
> 
> That is true, although you could reuse this argument for pretty much
> everything else, and let all userland be reimplemened in kernel.

No.  "X > Y" does not imply "for all X for all Y, X > Y".

Thor