Commit 91fb309d authored by Horace Chen's avatar Horace Chen Committed by Alex Deucher
Browse files

drm/amdgpu: race issue when jobs on 2 ring timeout 



Fix a racing issue when jobs on 2 rings timeout simultaneously.

If 2 rings timed out at the same time, the
amdgpu_device_gpu_recover will be reentered. Then the
adev->gmc.xgmi.head will be grabbed by 2 local linked list,
which may cause wild pointer issue in iterating.

lock the device earily to prevent the node be added to 2
different lists.

also increase karma for the skipped job since the job is also
timed out and should be guilty.

Signed-off-by: default avatarHorace Chen <horace.chen@amd.com>
Reviewed-by: default avatarAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent eda1068d

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

+59 −10
Original line number Diff line number Diff line
@@ -4461,6 +4461,46 @@ static void amdgpu_device_unlock_adev(struct amdgpu_device *adev) 
	up_write(&adev->reset_sem);

}



/*

 * to lockup a list of amdgpu devices in a hive safely, if not a hive

 * with multiple nodes, it will be similar as amdgpu_device_lock_adev.

 *

 * unlock won't require roll back.

 */

static int amdgpu_device_lock_hive_adev(struct amdgpu_device *adev, struct amdgpu_hive_info *hive)

{

	struct amdgpu_device *tmp_adev = NULL;



	if (adev->gmc.xgmi.num_physical_nodes > 1) {

		if (!hive) {

			dev_err(adev->dev, "Hive is NULL while device has multiple xgmi nodes");

			return -ENODEV;

		}

		list_for_each_entry(tmp_adev, &hive->device_list, gmc.xgmi.head) {

			if (!amdgpu_device_lock_adev(tmp_adev, hive))

				goto roll_back;

		}

	} else if (!amdgpu_device_lock_adev(adev, hive))

		return -EAGAIN;



	return 0;

roll_back:

	if (!list_is_first(&tmp_adev->gmc.xgmi.head, &hive->device_list)) {

		/*

		 * if the lockup iteration break in the middle of a hive,

		 * it may means there may has a race issue,

		 * or a hive device locked up independently.

		 * we may be in trouble and may not, so will try to roll back

		 * the lock and give out a warnning.

		 */

		dev_warn(tmp_adev->dev, "Hive lock iteration broke in the middle. Rolling back to unlock");

		list_for_each_entry_continue_reverse(tmp_adev, &hive->device_list, gmc.xgmi.head) {

			amdgpu_device_unlock_adev(tmp_adev);

		}

	}

	return -EAGAIN;

}



static void amdgpu_device_resume_display_audio(struct amdgpu_device *adev)

{

	struct pci_dev *p = NULL;
@@ -4574,11 +4614,29 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev, 
			DRM_INFO("Bailing on TDR for s_job:%llx, hive: %llx as another already in progress",

				job ? job->base.id : -1, hive->hive_id);

			amdgpu_put_xgmi_hive(hive);

			if (job)

				drm_sched_increase_karma(&job->base);

			return 0;

		}

		mutex_lock(&hive->hive_lock);

	}



	/*

	 * lock the device before we try to operate the linked list

	 * if didn't get the device lock, don't touch the linked list since

	 * others may iterating it.

	 */

	r = amdgpu_device_lock_hive_adev(adev, hive);

	if (r) {

		dev_info(adev->dev, "Bailing on TDR for s_job:%llx, as another already in progress",

					job ? job->base.id : -1);



		/* even we skipped this reset, still need to set the job to guilty */

		if (job)

			drm_sched_increase_karma(&job->base);

		goto skip_recovery;

	}



	/*

	 * Build list of devices to reset.

	 * In case we are in XGMI hive mode, resort the device list
@@ -4586,8 +4644,6 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev, 
	 */

	INIT_LIST_HEAD(&device_list);

	if (adev->gmc.xgmi.num_physical_nodes > 1) {

		if (!hive)

			return -ENODEV;

		if (!list_is_first(&adev->gmc.xgmi.head, &hive->device_list))

			list_rotate_to_front(&adev->gmc.xgmi.head, &hive->device_list);

		device_list_handle = &hive->device_list;
@@ -4598,13 +4654,6 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev, 


	/* block all schedulers and reset given job's ring */

	list_for_each_entry(tmp_adev, device_list_handle, gmc.xgmi.head) {

		if (!amdgpu_device_lock_adev(tmp_adev, hive)) {

			dev_info(tmp_adev->dev, "Bailing on TDR for s_job:%llx, as another already in progress",

				  job ? job->base.id : -1);

			r = 0;

			goto skip_recovery;

		}



		/*

		 * Try to put the audio codec into suspend state

		 * before gpu reset started.
@@ -4742,7 +4791,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev, 
		amdgpu_put_xgmi_hive(hive);

	}



	if (r)

	if (r && r != -EAGAIN)

		dev_info(adev->dev, "GPU reset end with ret = %d\n", r);

	return r;

}