Re: [PATCH 4.4 31/43] mm: fix cache mode tracking in vm_insert_mixed()

[Greg Kroah-Hartman]

On Fri, Sep 07, 2018 at 06:05:23PM +0100, Ben Hutchings wrote:
> On Tue, 2018-08-14 at 19:18 +0200, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Dan Williams <dan.j.williams@xxxxxxxxx>
> > 
> > commit 87744ab3832b83ba71b931f86f9cfdb000d07da5 upstream
> > 
> > vm_insert_mixed() unlike vm_insert_pfn_prot() and vmf_insert_pfn_pmd(),
> > fails to check the pgprot_t it uses for the mapping against the one
> > recorded in the memtype tracking tree.  Add the missing call to
> > track_pfn_insert() to preclude cases where incompatible aliased mappings
> > are established for a given physical address range.
> [...]
> 
> This apparently breaks a number of DRM drivers.  The upstream fixes
> are:
> 
> 8ef4227615e1 x86/io: add interface to reserve io memtype for a resource range. (v1.1)
> 7cf321d118a8 drm/drivers: add support for using the arch wc mapping API.
> 
> They appear to apply cleanly to 4.4-stable.  They are included in 4.9
> so no other stable branch needs them.

Thanks, now queued up.

greg k-h