This is a note to let you know that I've just added the patch titled
drm/ttm: stop calling tt_swapin in vm_access
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-ttm-stop-calling-tt_swapin-in-vm_access.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 13cba41d191cd26c27350bb922aaf7d074d1ae74
Author: Matthew Auld <matthew.auld@xxxxxxxxx>
Date: Mon Sep 27 12:41:02 2021 +0100
drm/ttm: stop calling tt_swapin in vm_access
[ Upstream commit f5d28856b89baab4232a9f841e565763fcebcdf9 ]
In commit:
commit 09ac4fcb3f255e9225967c75f5893325c116cdbe
Author: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Date: Thu Jul 13 17:01:16 2017 -0400
drm/ttm: Implement vm_operations_struct.access v2
we added the vm_access hook, where we also directly call tt_swapin for
some reason. If something is swapped-out then the ttm_tt must also be
unpopulated, and since access_kmap should also call tt_populate, if
needed, then swapping-in will already be handled there.
If anything, calling tt_swapin directly here would likely always fail
since the tt->pages won't yet be populated, or worse since the tt->pages
array is never actually cleared in unpopulate this might lead to a nasty
uaf.
Fixes: 09ac4fcb3f25 ("drm/ttm: Implement vm_operations_struct.access v2")
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Reviewed-by: Christian König <christian.koenig@xxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20210927114114.152310-1-matthew.auld@xxxxxxxxx
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index f56be5bc0861e..5b9b7fd01a692 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -519,11 +519,6 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
switch (bo->resource->mem_type) {
case TTM_PL_SYSTEM:
- if (unlikely(bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
- ret = ttm_tt_swapin(bo->ttm);
- if (unlikely(ret != 0))
- return ret;
- }
fallthrough;
case TTM_PL_TT:
ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
