6.18-stable review patch. If anyone has any objections, please let me know.
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From: Boris Brezillon boris.brezillon@collabora.com
[ Upstream commit 98dd5143447af0ee33551776d8b2560c35d0bc4a ]
If the MMU is down, panthor_vm_unmap_range() might return an error. We expect the page table to be updated still, and if the MMU is blocked, the rest of the GPU should be blocked too, so no risk of accessing physical memory returned to the system (which the current code doesn't cover for anyway).
Proceed with the rest of the cleanup instead of bailing out and leaving the va_node inserted in the drm_mm, which leads to UAF when other adjacent nodes are removed from the drm_mm tree.
Reported-by: Lars-Ivar Hesselberg Simonsen lars-ivar.simonsen@arm.com Closes: https://gitlab.freedesktop.org/panfrost/linux/-/issues/57 Fixes: 8a1cc07578bf ("drm/panthor: Add GEM logical block") Signed-off-by: Boris Brezillon boris.brezillon@collabora.com Reviewed-by: Liviu Dudau liviu.dudau@arm.com Link: https://patch.msgid.link/20251031154818.821054-2-boris.brezillon@collabora.c... Signed-off-by: Liviu Dudau liviu.dudau@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/panthor/panthor_gem.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c index 3f43686f01958..14ed09d700f2f 100644 --- a/drivers/gpu/drm/panthor/panthor_gem.c +++ b/drivers/gpu/drm/panthor/panthor_gem.c @@ -86,7 +86,6 @@ static void panthor_gem_free_object(struct drm_gem_object *obj) void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo) { struct panthor_vm *vm; - int ret;
if (IS_ERR_OR_NULL(bo)) return; @@ -94,18 +93,11 @@ void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo) vm = bo->vm; panthor_kernel_bo_vunmap(bo);
- if (drm_WARN_ON(bo->obj->dev, - to_panthor_bo(bo->obj)->exclusive_vm_root_gem != panthor_vm_root_gem(vm))) - goto out_free_bo; - - ret = panthor_vm_unmap_range(vm, bo->va_node.start, bo->va_node.size); - if (ret) - goto out_free_bo; - + drm_WARN_ON(bo->obj->dev, + to_panthor_bo(bo->obj)->exclusive_vm_root_gem != panthor_vm_root_gem(vm)); + panthor_vm_unmap_range(vm, bo->va_node.start, bo->va_node.size); panthor_vm_free_va(vm, &bo->va_node); drm_gem_object_put(bo->obj); - -out_free_bo: panthor_vm_put(vm); kfree(bo); }