Rather than getting some hard to debug uaf, add some warns to hopefully catch issues with userfault_count being non-zero when destroying the object. Also if we somehow add an object to lmem_userfault_list that somehow doesn't map lmem. References: https://gitlab.freedesktop.org/drm/intel/-/issues/7469 Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx> Cc: Anshuman Gupta <anshuman.gupta@xxxxxxxxx> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx> Cc: Nirmoy Das <nirmoy.das@xxxxxxxxx> --- drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c index 9421dc4dc98f..2c8b2d5ae903 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c @@ -1098,6 +1098,8 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) spin_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); list_add(&obj->userfault_link, &to_i915(obj->base.dev)->runtime_pm.lmem_userfault_list); spin_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); + + GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(bo->resource)); } if (wakeref & CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) @@ -1180,6 +1182,8 @@ static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj) } } + GEM_WARN_ON(obj->userfault_count); + ttm_bo_unmap_virtual(i915_gem_to_ttm(obj)); if (wakeref) -- 2.38.1
