On Tue, Aug 5, 2025 at 3:56 PM Sasha Levin <sas...@kernel.org> wrote:
>
> Restructure submit_lock_objects() to use a single loop with break
> statements to fix objtool warning:
>
> drivers/gpu/drm/msm/msm.o: warning: objtool: submit_lock_objects+0x451:
> sibling call from callable instruction with modified stack frame
>
> The drm_exec_until_all_locked() macro uses computed gotos internally
> for its retry loop. Having return statements inside this macro, or
> immediately after it in certain code paths, confuses objtool's static
> analysis of stack frames, causing it to incorrectly flag tail call
> optimizations.
Maybe we should instead just split out a separate
submit_lock_objects_vmbind() and restore the error path 'goto error'
instead of returning from within the loop? Ie. basically revert
submit_lock_objects to the way it was before commit 92395af63a99
("drm/msm: Add VM_BIND submitqueue"), and then move the rest into a
new fxn (with 'goto error' instead of 'return ret'? In retrospect the
vmbind case is kinda just shoehorned into the existing fxn.
I can type up this version if you have better things to do.
BR,
-R
> Fixes: 92395af63a99 ("drm/msm: Add VM_BIND submitqueue")
> Signed-off-by: Sasha Levin <sas...@kernel.org>
> ---
> drivers/gpu/drm/msm/msm_gem_submit.c | 43 ++++++++++++----------------
> 1 file changed, 19 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c
> b/drivers/gpu/drm/msm/msm_gem_submit.c
> index 5f8e939a5906..253347b6e328 100644
> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> @@ -276,46 +276,41 @@ static int submit_lock_objects(struct msm_gem_submit
> *submit)
> {
> unsigned flags = DRM_EXEC_INTERRUPTIBLE_WAIT;
> struct drm_exec *exec = &submit->exec;
> - int ret;
> + int ret = 0;
>
> - if (msm_context_is_vmbind(submit->queue->ctx)) {
> + if (msm_context_is_vmbind(submit->queue->ctx))
> flags |= DRM_EXEC_IGNORE_DUPLICATES;
>
> - drm_exec_init(&submit->exec, flags, submit->nr_bos);
> + drm_exec_init(&submit->exec, flags, submit->nr_bos);
>
> - drm_exec_until_all_locked (&submit->exec) {
> + drm_exec_until_all_locked (&submit->exec) {
> + if (msm_context_is_vmbind(submit->queue->ctx)) {
> ret = drm_gpuvm_prepare_vm(submit->vm, exec, 1);
> drm_exec_retry_on_contention(exec);
> if (ret)
> - return ret;
> + break;
>
> ret = drm_gpuvm_prepare_objects(submit->vm, exec, 1);
> drm_exec_retry_on_contention(exec);
> if (ret)
> - return ret;
> - }
> -
> - return 0;
> - }
> -
> - drm_exec_init(&submit->exec, flags, submit->nr_bos);
> -
> - drm_exec_until_all_locked (&submit->exec) {
> - ret = drm_exec_lock_obj(&submit->exec,
> - drm_gpuvm_resv_obj(submit->vm));
> - drm_exec_retry_on_contention(&submit->exec);
> - if (ret)
> - return ret;
> - for (unsigned i = 0; i < submit->nr_bos; i++) {
> - struct drm_gem_object *obj = submit->bos[i].obj;
> - ret = drm_exec_prepare_obj(&submit->exec, obj, 1);
> + break;
> + } else {
> + ret = drm_exec_lock_obj(&submit->exec,
> +
> drm_gpuvm_resv_obj(submit->vm));
> drm_exec_retry_on_contention(&submit->exec);
> if (ret)
> - return ret;
> + break;
> + for (unsigned i = 0; i < submit->nr_bos; i++) {
> + struct drm_gem_object *obj =
> submit->bos[i].obj;
> + ret = drm_exec_prepare_obj(&submit->exec,
> obj, 1);
> + drm_exec_retry_on_contention(&submit->exec);
> + if (ret)
> + break;
> + }
> }
> }
>
> - return 0;
> + return ret;
> }
>
> static int submit_fence_sync(struct msm_gem_submit *submit)
> --
> 2.39.5
>
