From b892d39199df8daa2ce6e65a111f5a15be58ae5b Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Thu, 31 Mar 2022 22:46:50 +0200
Subject: [PATCH] drm/sched: Check locking in
 drm_sched_job_add_implicit_dependencies
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

You really need to hold the reservation here or all kinds of funny
things can happen between grabbing the dependencies and inserting the
new fences.

v2: Fix commit summary (Christian)

Acked-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Luben Tuikov <luben.tuikov@amd.com>
Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220331204651.2699107-4-daniel.vetter@ffwll.ch
---
 drivers/gpu/drm/scheduler/sched_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index b81fceb..c5660b0 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -703,6 +703,8 @@ int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 	struct dma_fence *fence;
 	int ret;
 
+	dma_resv_assert_held(obj->resv);
+
 	dma_resv_for_each_fence(&cursor, obj->resv, write, fence) {
 		/* Make sure to grab an additional ref on the added fence */
 		dma_fence_get(fence);
-- 
2.7.4