On Fri, Oct 31, 2025 at 04:48:15PM +0100, Boris Brezillon wrote: > 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 <[email protected]> > Closes: https://gitlab.freedesktop.org/panfrost/linux/-/issues/57 > Fixes: 8a1cc07578bf ("drm/panthor: Add GEM logical block") > Signed-off-by: Boris Brezillon <[email protected]>
Reviewed-by: Liviu Dudau <[email protected]> Best regards, Liviu > --- > 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 7e7d2f223cfa..f369cc3e2a5f 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -87,7 +87,6 @@ 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; > @@ -95,18 +94,11 @@ 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); > } > -- > 2.51.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯
