Commit 8c1d3f79 authored by Mao Jinlong's avatar Mao Jinlong Committed by Suzuki K Poulose
Browse files

coresight: core: Fix coresight device probe failure issue 



It is possibe that probe failure issue happens when the device
and its child_device's probe happens at the same time.
In coresight_make_links, has_conns_grp is true for parent, but
has_conns_grp is false for child device as has_conns_grp is set
to true in coresight_create_conns_sysfs_group. The probe of parent
device will fail at this condition. Add has_conns_grp check for
child device before make the links and make the process from
device_register to connection_create be atomic to avoid this
probe failure issue.

Cc: stable@vger.kernel.org
Suggested-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Suggested-by: default avatarMike Leach <mike.leach@linaro.org>
Signed-off-by: default avatarMao Jinlong <quic_jinlmao@quicinc.com>
Link: https://lore.kernel.org/r/20220309142206.15632-1-quic_jinlmao@quicinc.com


[ Added Cc stable ]
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
parent c86dd986

drivers/hwtracing/coresight/coresight-core.c

+22 −11
Original line number Diff line number Diff line
@@ -1379,7 +1379,7 @@ static int coresight_fixup_device_conns(struct coresight_device *csdev) 
			continue;

		conn->child_dev =

			coresight_find_csdev_by_fwnode(conn->child_fwnode);

		if (conn->child_dev) {

		if (conn->child_dev && conn->child_dev->has_conns_grp) {

			ret = coresight_make_links(csdev, conn,

						   conn->child_dev);

			if (ret)
@@ -1571,6 +1571,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) 
	int nr_refcnts = 1;

	atomic_t *refcnts = NULL;

	struct coresight_device *csdev;

	bool registered = false;



	csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);

	if (!csdev) {
@@ -1591,7 +1592,8 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) 
	refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);

	if (!refcnts) {

		ret = -ENOMEM;

		goto err_free_csdev;

		kfree(csdev);

		goto err_out;

	}



	csdev->refcnt = refcnts;
@@ -1616,6 +1618,13 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) 
	csdev->dev.fwnode = fwnode_handle_get(dev_fwnode(desc->dev));

	dev_set_name(&csdev->dev, "%s", desc->name);



	/*

	 * Make sure the device registration and the connection fixup

	 * are synchronised, so that we don't see uninitialised devices

	 * on the coresight bus while trying to resolve the connections.

	 */

	mutex_lock(&coresight_mutex);



	ret = device_register(&csdev->dev);

	if (ret) {

		put_device(&csdev->dev);
@@ -1623,7 +1632,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) 
		 * All resources are free'd explicitly via

		 * coresight_device_release(), triggered from put_device().

		 */

		goto err_out;

		goto out_unlock;

	}



	if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
@@ -1638,11 +1647,11 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) 
			 * from put_device(), which is in turn called from

			 * function device_unregister().

			 */

			goto err_out;

			goto out_unlock;

		}

	}



	mutex_lock(&coresight_mutex);

	/* Device is now registered */

	registered = true;



	ret = coresight_create_conns_sysfs_group(csdev);

	if (!ret)
@@ -1652,16 +1661,18 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) 
	if (!ret && cti_assoc_ops && cti_assoc_ops->add)

		cti_assoc_ops->add(csdev);



out_unlock:

	mutex_unlock(&coresight_mutex);

	if (ret) {

	/* Success */

	if (!ret)

		return csdev;



	/* Unregister the device if needed */

	if (registered) {

		coresight_unregister(csdev);

		return ERR_PTR(ret);

	}



	return csdev;



err_free_csdev:

	kfree(csdev);

err_out:

	/* Cleanup the connection information */

	coresight_release_platform_data(NULL, desc->pdata);