Re: [patch] mm: recheck lock rlim after f_op->mmap() method

[Dmitry Monakhov <dmonakhov@sw.ru>]

On 10:32 Срд 11 Июл     , Christoph Hellwig wrote:
> On Tue, Jul 10, 2007 at 06:27:05PM +0100, Hugh Dickins wrote:
> > On Mon, 9 Jul 2007, Dmitry Monakhov wrote:
> > > Some device drivers can change vm_flags in their f_op->mmap
> > > method. In order to be on the safe side we have to recheck
> > > lock rlimit. Now we have to check lock rlimit from two places,
> > > let's move this common code to helper functon.
> > > 
> > > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
> > > ---
> > >  mm/mmap.c |   33 ++++++++++++++++++++++++++-------
> > >  1 files changed, 26 insertions(+), 7 deletions(-)
> > 
> > Or would this simpler patch be the right one?  I suspect the
> > mspec driver only says VM_LOCKED because of a deep-seated but
> > irrational fear that its pages might fall into reclaim.
> 
> Looks good.  We probably should add a debug check to do_mmap_pgoff
> so that ->mmap methods don't change flags that are not for drivers.
As result fglrx totally goes crazy, because it change vm_flags
even from  ->nopage() calback :)
>