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

[Greg KH <greg@kroah.com>]

On Tue, Aug 04, 2015 at 12:39:13AM +0300, Kirill A. Shutemov wrote:
> On Mon, Aug 03, 2015 at 01:36:23PM -0700, Greg KH wrote:
> > On Mon, Aug 03, 2015 at 10:40:55PM +0300, Kirill A. Shutemov wrote:
> > > 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.
> > 
> > Can you provide that backport, it isn't a direct cherry-pick.
> 
> Patches are in attach.
> 
> 0001-mm-avoid-setting-up-anonymous-pages-3.18.patch is rebased onto v3.18.
> 
> 0001-mm-avoid-setting-up-anonymous-pages-3.14.patch is rebased onto v3.14,
> also applies cleanly to v3.12, v3.10, v3.4, v3.2.

Thanks, I've taken this patch now for 3.10 and 3.14.

greg k-h