From 625b74460ec0978979f883fbee117e1b97e6e35e Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Mon, 7 Nov 2022 16:54:13 +0000 Subject: [PATCH] drm/i915/ttm: fix uaf with lmem_userfault_list handling In the fault handler, make sure we check if the BO maps lmem after we schedule the migration, since the current resource might change from lmem to smem, if the pages are in the non-cpu visible portion of lmem. This then leads to adding the object to the lmem_userfault_list even though the current resource is no longer lmem. If we then destroy the object, the list might still contain a link to the now free object, since we only remove it if the object is still in lmem. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7469 Fixes: ad74457a6b5a ("drm/i915/dgfx: Release mmap on rpm suspend") Signed-off-by: Matthew Auld Cc: Anshuman Gupta Cc: Rodrigo Vivi Cc: Andrzej Hajda Cc: Nirmoy Das Reviewed-by: Andrzej Hajda Link: https://patchwork.freedesktop.org/patch/msgid/20221107165414.56970-1-matthew.auld@intel.com --- drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c index 25129af..9421dc4 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c @@ -1048,9 +1048,6 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) return VM_FAULT_SIGBUS; } - if (i915_ttm_cpu_maps_iomem(bo->resource)) - wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm); - if (!i915_ttm_resource_mappable(bo->resource)) { int err = -ENODEV; int i; @@ -1078,6 +1075,9 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) } } + if (i915_ttm_cpu_maps_iomem(bo->resource)) + wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm); + if (drm_dev_enter(dev, &idx)) { ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot, TTM_BO_VM_NUM_PREFAULT); -- 2.7.4