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coresight: core: Fix coresight device probe failure issue

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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: Suzuki K Poulose <suzuki.poulose@arm.com>
Suggested-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
Link: https://lore.kernel.org/r/20220309142206.15632-1-quic_jinlmao@quicinc.com
[ Added Cc stable ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
This commit is contained in:
Mao Jinlong 2022-03-09 06:22:06 -08:00 committed by Suzuki K Poulose
parent c86dd98691
commit 8c1d3f79d9
1 changed files with 22 additions and 11 deletions
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33
drivers/hwtracing/coresight/coresight-core.c
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@ -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);