mm: fix cache mode tracking in vm_insert_mixed() breaks AMDGPU [was: Re: Latest testing with drm-next-4.9-wip and latest LLVM/mesa stack - Regression in PowerPlay/DPM on CIK?]
michel at daenzer.net
Fri Oct 14 01:33:21 UTC 2016
[ Adding Dan Williams and dri-devel ]
On 14/10/16 03:28 AM, Shawn Starr wrote:
> Hello AMD folks,
> I have discovered a problem in Linus master that affects AMDGPU, nobody would
> notice this in drm-next-4.9-wip since its not in this repo.
> 87744ab3832b83ba71b931f86f9cfdb000d07da5 is the first bad commit
> commit 87744ab3832b83ba71b931f86f9cfdb000d07da5
> Author: Dan Williams <dan.j.williams at intel.com>
> Date: Fri Oct 7 17:00:18 2016 -0700
> mm: fix cache mode tracking in vm_insert_mixed()
> 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.
> Link: http://lkml.kernel.org/r/
> 147328717909.35069.14256589123570653697.stgit at dwillia2-
> Signed-off-by: Dan Williams <dan.j.williams at intel.com>
> Cc: David Airlie <airlied at linux.ie>
> Cc: Matthew Wilcox <mawilcox at microsoft.com>
> Cc: Ross Zwisler <ross.zwisler at linux.intel.com>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> :040000 040000 7517c0019fe49c1830b5a1d81f1dc099c5aab98a
> fd497a604a2af5995db2b8ed1e9c640bede6adf3 M mm
> Removal of this patch stops graphics stalls.
Thanks for bisecting this Shawn.
> A friend of mine mentions,
> "looks like a graphics thingy you depend on is requesting a mapping with a
> not-allowed cache mode, and now you are (rightfully) getting errors?"
It would be nice to get some more specific pointers what amdgpu (or
maybe ttm, since that calls vm_insert_mixed in ttm_bo_vm_fault) might be
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
More information about the dri-devel