From f5d28856b89baab4232a9f841e565763fcebcdf9 Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Mon, 27 Sep 2021 12:41:02 +0100 Subject: [PATCH] drm/ttm: stop calling tt_swapin in vm_access MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit In commit: commit 09ac4fcb3f255e9225967c75f5893325c116cdbe Author: Felix Kuehling 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 Cc: Thomas Hellström Cc: Christian König Reviewed-by: Thomas Hellström Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20210927114114.152310-1-matthew.auld@intel.com Signed-off-by: Christian König --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index f56be5b..5b9b7fd 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); -- 2.7.4