Re: [Linaro-mm-sig] [PATCH 2/2] drm/msm: Restore error return on invalid fence

On Mon, Nov 15, 2021 at 6:43 AM Akhil P Oommen akhilpo@codeaurora.org wrote:

On 11/12/2021 12:54 AM, Rob Clark wrote:

...

From: Rob Clark robdclark@chromium.org

When converting to use an idr to map userspace fence seqno values back to a dma_fence, we lost the error return when userspace passes seqno that is larger than the last submitted fence. Restore this check.

Reported-by: Akhil P Oommen akhilpo@codeaurora.org Fixes: a61acbbe9cf8 ("drm/msm: Track "seqno" fences by idr") Signed-off-by: Rob Clark robdclark@chromium.org

---

Note: I will rebase "drm/msm: Handle fence rollover" on top of this, to simplify backporting this patch to stable kernels

drivers/gpu/drm/msm/msm_drv.c | 6 ++++++ drivers/gpu/drm/msm/msm_gem_submit.c | 1 + drivers/gpu/drm/msm/msm_gpu.h | 3 +++ 3 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index cb14d997c174..56500eb5219e 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -967,6 +967,12 @@ static int wait_fence(struct msm_gpu_submitqueue *queue, uint32_t fence_id, struct dma_fence *fence; int ret;

• if (fence_id > queue->last_fence) {
  

But fence_id can wrap around and then this check won't be valid.

that is correct, but see my note about rebasing "drm/msm: Handle fence rollover" on top of this patch, so this patch could be more easily cherry-picked to stable/lts branches

BR, -R

-Akhil.

...

•         DRM_ERROR_RATELIMITED("waiting on invalid fence: %u (of %u)\n",
  

•                               fence_id, queue->last_fence);
  

•         return -EINVAL;
  

• }
  

• /*
   * Map submitqueue scoped "seqno" (which is actually an idr key)
   * back to underlying dma-fence
  

diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c index 151d19e4453c..a38f23be497d 100644 --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -911,6 +911,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, drm_sched_entity_push_job(&submit->base, queue->entity);

  args->fence = submit->fence_id;

• queue->last_fence = submit->fence_id;
  
  msm_reset_syncobjs(syncobjs_to_reset, args->nr_in_syncobjs);
  msm_process_post_deps(post_deps, args->nr_out_syncobjs,
  

diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h index bd4e0024033e..e73a5bb03544 100644 --- a/drivers/gpu/drm/msm/msm_gpu.h +++ b/drivers/gpu/drm/msm/msm_gpu.h @@ -376,6 +376,8 @@ static inline int msm_gpu_convert_priority(struct msm_gpu *gpu, int prio,

• @ring_nr: the ringbuffer used by this submitqueue, which is determined

•         by the submitqueue's priority
  

• @faults: the number of GPU hangs associated with this submitqueue

• • @last_fence: the sequence number of the last allocated fence (for error

• •         checking)
    

  • @ctx: the per-drm_file context associated with the submitqueue (ie.

  •         which set of pgtables do submits jobs associated with the
    

  •         submitqueue use)
    

@@ -391,6 +393,7 @@ struct msm_gpu_submitqueue { u32 flags; u32 ring_nr; int faults;

• uint32_t last_fence;
  struct msm_file_private *ctx;
  struct list_head node;
  struct idr fence_idr;