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drm/ttm: stop calling tt_swapin in vm_access 

In commit:

commit 09ac4fcb3f
Author: Felix Kuehling <Felix.Kuehling@amd.com>
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: 09ac4fcb3f ("drm/ttm: Implement vm_operations_struct.access v2")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Christian König <christian.koenig@amd.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210927114114.152310-1-matthew.auld@intel.com
Signed-off-by: Christian König <christian.koenig@amd.com>
This commit is contained in:
Matthew Auld 2021-09-27 12:41:02 +01:00 committed by Christian König
parent 78aa20fa43
commit f5d28856b8
1 changed files with 0 additions and 5 deletions
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5
drivers/gpu/drm/ttm/ttm_bo_vm.c
View File

@ -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);