It makes sense for a BO to move after a process has requested exclusive RW access on it (e.g. because the BO used to be located in unmappable VRAM and we intercepted the CPU access from the fault handler). If we let the ghost object inherit cpu_writers from the original object, ttm_bo_release_list() will raise a kernel BUG when the ghost object is destroyed. This can be reproduced with the nouveau driver on nv5x. Reported-by: Marcin Slusarz <marcin.slusarz@xxxxxxxxx> Signed-off-by: Francisco Jerez <currojerez@xxxxxxxxxx> --- drivers/gpu/drm/ttm/ttm_bo_util.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 7cffb3e..3451a82 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -351,6 +351,7 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo, INIT_LIST_HEAD(&fbo->lru); INIT_LIST_HEAD(&fbo->swap); fbo->vm_node = NULL; + atomic_set(&fbo->cpu_writers, 0); fbo->sync_obj = driver->sync_obj_ref(bo->sync_obj); kref_init(&fbo->list_kref); -- 1.6.4.4 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
