drm/etnaviv: (re-)protect fence allocation with GPU mutex

The fence allocation needs to be protected by the GPU mutex, otherwise
the fence seqnos of concurrent submits might not match the insertion order
of the jobs in the kernel ring. This breaks the assumption that jobs
complete with monotonically increasing fence seqnos.

Fixes: d9853490176c (drm/etnaviv: take GPU lock later in the submit process)
CC: stable@vger.kernel.org #4.9+
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 130d7d517a19a180ca7f2e744131aeabc554564b..da48819ff2e6550c0a7d6206569d85e8a880c0c5 100644 (file)
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1311,6 +1311,8 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu,
                goto out_pm_put;
        }
 
+       mutex_lock(&gpu->lock);
+
        fence = etnaviv_gpu_fence_alloc(gpu);
        if (!fence) {
                event_free(gpu, event);
@@ -1318,8 +1320,6 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu,
                goto out_pm_put;
        }
 
-       mutex_lock(&gpu->lock);
-
        gpu->event[event].fence = fence;
        submit->fence = fence->seqno;
        gpu->active_fence = submit->fence;