Re: [PATCH] [4.2 fix] x86, mpx: do not set ->vm_ops on mpx VMAs

[Kirill A. Shutemov]

On Mon, Aug 03, 2015 at 09:19:14AM -0700, Greg KH wrote:
> On Mon, Aug 03, 2015 at 01:34:28PM +0300, Kirill A. Shutemov wrote:
> > Greg KH wrote:
> > > On Mon, Jul 20, 2015 at 02:29:58PM -0700, Dave Hansen wrote:
> > > > 
> > > > (sorry for the spam, I screwed up the stable@ address).
> > > > 
> > > > BTW, thanks to Kirill for doing this patch!  He posted it to LKML
> > > > but we need to ensure it is picked up for 4.2 and any -stable
> > > > kernels where this commit is applied:
> > > > 
> > > >     	6b7339f4: mm: avoid setting up anonymous pages into file mapping
> > > > 
> > > > That broke MPX support because MPX sets a vma->vm_ops on an
> > > > anonymous VMA.  We need this patch to make it work again,
> > > > basically removing MPX's use of ->vm_ops.  Kirill made me aware
> > > > of this long ago, but I didn't double-check that his fix got
> > > > submitted and merged.
> > > > 
> > > > I (Dave) fixed up a minor merge conflict and added the
> > > > try_unmap_single_bt() use of is_mpx_vma() (which were added
> > > > post-4.1).
> > > > 
> > > > Note for -stable: The first hunk may not apply cleanly because of
> > > > other activity in arch/x86/mm/mmap.c, but should be trivial to
> > > > apply by hand.  Hunk #5 on mpx.c is only present on 4.2-rc kernels.
> > > 
> > > Can someone send a version that is known to apply, you don't want to
> > > rely on me to get it right :)
> > 
> > Here it is.
> > 
> > MPX support was introduced in 3.19, so it only need to be applied to
> > 4.1-stable.
> 
> Thanks, now applied.

Just to make clear: we don't need MPX patch for older stables, but we
*do* need 6b7339f4 (mm: avoid setting up anonymous pages into file
mapping) to be ported into all stables.

-- 
 Kirill A. Shutemov
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