* [PATCH v2] coresight: core: Fix coresight device probe failure issue
@ 2022-03-04 8:23 Mao Jinlong
2022-03-08 11:56 ` Suzuki K Poulose
0 siblings, 1 reply; 5+ messages in thread
From: Mao Jinlong @ 2022-03-04 8:23 UTC (permalink / raw)
To: Mathieu Poirier, Suzuki K Poulose, Mike Leach, Leo Yan,
Alexander Shishkin
Cc: Mao Jinlong, coresight, linux-arm-kernel, linux-kernel,
linux-arm-msm, Tingwei Zhang, Yuanfang Zhang, Tao Zhang,
Hao Zhang
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.
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>
---
drivers/hwtracing/coresight/coresight-core.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 88653d1c06a4..b3e3bc59c09b 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1382,7 +1382,7 @@ 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)
@@ -1594,7 +1594,8 @@ 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;
@@ -1619,8 +1620,10 @@ 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);
+ mutex_lock(&coresight_mutex);
ret = device_register(&csdev->dev);
if (ret) {
+ mutex_unlock(&coresight_mutex);
put_device(&csdev->dev);
/*
* All resources are free'd explicitly via
@@ -1634,6 +1637,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
ret = etm_perf_add_symlink_sink(csdev);
if (ret) {
+ mutex_unlock(&coresight_mutex);
device_unregister(&csdev->dev);
/*
* As with the above, all resources are free'd
@@ -1645,8 +1649,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
}
}
- mutex_lock(&coresight_mutex);
-
ret = coresight_create_conns_sysfs_group(csdev);
if (!ret)
ret = coresight_fixup_device_conns(csdev);
@@ -1663,8 +1665,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
return csdev;
-err_free_csdev:
- kfree(csdev);
err_out:
/* Cleanup the connection information */
coresight_release_platform_data(NULL, desc->pdata);
--
2.17.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] coresight: core: Fix coresight device probe failure issue
2022-03-04 8:23 [PATCH v2] coresight: core: Fix coresight device probe failure issue Mao Jinlong
@ 2022-03-08 11:56 ` Suzuki K Poulose
2022-03-08 13:36 ` Suzuki K Poulose
0 siblings, 1 reply; 5+ messages in thread
From: Suzuki K Poulose @ 2022-03-08 11:56 UTC (permalink / raw)
To: Mao Jinlong, Mathieu Poirier, Mike Leach, Leo Yan, Alexander Shishkin
Cc: coresight, linux-arm-kernel, linux-kernel, linux-arm-msm,
Tingwei Zhang, Yuanfang Zhang, Tao Zhang, Hao Zhang
Hi Jinlong
On 04/03/2022 08:23, Mao Jinlong wrote:
> 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.
>
> 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>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 88653d1c06a4..b3e3bc59c09b 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -1382,7 +1382,7 @@ 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)
> @@ -1594,7 +1594,8 @@ 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;
> @@ -1619,8 +1620,10 @@ 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);
>
> + mutex_lock(&coresight_mutex);
> ret = device_register(&csdev->dev);
> if (ret) {
> + mutex_unlock(&coresight_mutex);
> put_device(&csdev->dev);
> /*
> * All resources are free'd explicitly via
> @@ -1634,6 +1637,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
> ret = etm_perf_add_symlink_sink(csdev);
>
> if (ret) {
> + mutex_unlock(&coresight_mutex);
> device_unregister(&csdev->dev);
> /*
> * As with the above, all resources are free'd
> @@ -1645,8 +1649,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
> }
> }
>
> - mutex_lock(&coresight_mutex);
> -
> ret = coresight_create_conns_sysfs_group(csdev);
> if (!ret)
> ret = coresight_fixup_device_conns(csdev);
> @@ -1663,8 +1665,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
>
> return csdev;
>
> -err_free_csdev:
> - kfree(csdev);
> err_out:
> /* Cleanup the connection information */
> coresight_release_platform_data(NULL, desc->pdata);
Could we consolidate the unlock sequence to a single point with
something like this (untested):
diff --git a/drivers/hwtracing/coresight/coresight-core.c
b/drivers/hwtracing/coresight/coresight-core.c
index af00dca8d1ac..198ee140c6e6 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -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 +1661,15 @@ 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);
--
2.35.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] coresight: core: Fix coresight device probe failure issue
2022-03-08 11:56 ` Suzuki K Poulose
@ 2022-03-08 13:36 ` Suzuki K Poulose
2022-03-09 2:57 ` Jinlong Mao
0 siblings, 1 reply; 5+ messages in thread
From: Suzuki K Poulose @ 2022-03-08 13:36 UTC (permalink / raw)
To: Mao Jinlong, Mathieu Poirier, Mike Leach, Leo Yan, Alexander Shishkin
Cc: coresight, linux-arm-kernel, linux-kernel, linux-arm-msm,
Tingwei Zhang, Yuanfang Zhang, Tao Zhang, Hao Zhang
On 08/03/2022 11:56, Suzuki K Poulose wrote:
> Hi Jinlong
>
> On 04/03/2022 08:23, Mao Jinlong wrote:
>> 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.
>>
>> 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>
>> ---
>> drivers/hwtracing/coresight/coresight-core.c | 12 ++++++------
>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>> b/drivers/hwtracing/coresight/coresight-core.c
>> index 88653d1c06a4..b3e3bc59c09b 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -1382,7 +1382,7 @@ 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)
>> @@ -1594,7 +1594,8 @@ 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;
>> @@ -1619,8 +1620,10 @@ 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);
>> + mutex_lock(&coresight_mutex);
>> ret = device_register(&csdev->dev);
>> if (ret) {
>> + mutex_unlock(&coresight_mutex);
>> put_device(&csdev->dev);
>> /*
>> * All resources are free'd explicitly via
>> @@ -1634,6 +1637,7 @@ struct coresight_device
>> *coresight_register(struct coresight_desc *desc)
>> ret = etm_perf_add_symlink_sink(csdev);
>> if (ret) {
>> + mutex_unlock(&coresight_mutex);
>> device_unregister(&csdev->dev);
>> /*
>> * As with the above, all resources are free'd
>> @@ -1645,8 +1649,6 @@ struct coresight_device
>> *coresight_register(struct coresight_desc *desc)
>> }
>> }
>> - mutex_lock(&coresight_mutex);
>> -
>> ret = coresight_create_conns_sysfs_group(csdev);
>> if (!ret)
>> ret = coresight_fixup_device_conns(csdev);
>> @@ -1663,8 +1665,6 @@ struct coresight_device
>> *coresight_register(struct coresight_desc *desc)
>> return csdev;
>> -err_free_csdev:
>> - kfree(csdev);
>> err_out:
>> /* Cleanup the connection information */
>> coresight_release_platform_data(NULL, desc->pdata);
>
> Could we consolidate the unlock sequence to a single point with
> something like this (untested):
>
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c
> b/drivers/hwtracing/coresight/coresight-core.c
> index af00dca8d1ac..198ee140c6e6 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -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 +1661,15 @@ 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);
> - }
Apologies, this should be preserved :
i.e,
if (registered) {
coresight_unregister(csdev);
return ERR_PTR(ret);
}
Thanks
Suzuki
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] coresight: core: Fix coresight device probe failure issue
2022-03-08 13:36 ` Suzuki K Poulose
@ 2022-03-09 2:57 ` Jinlong Mao
2022-03-09 14:27 ` Jinlong Mao
0 siblings, 1 reply; 5+ messages in thread
From: Jinlong Mao @ 2022-03-09 2:57 UTC (permalink / raw)
To: Suzuki K Poulose, Mathieu Poirier, Mike Leach, Leo Yan,
Alexander Shishkin
Cc: coresight, linux-arm-kernel, linux-kernel, linux-arm-msm,
Tingwei Zhang, Yuanfang Zhang, Tao Zhang, Hao Zhang
Hi Suzuki,
On 3/8/2022 9:36 PM, Suzuki K Poulose wrote:
> On 08/03/2022 11:56, Suzuki K Poulose wrote:
>> Hi Jinlong
>>
>> On 04/03/2022 08:23, Mao Jinlong wrote:
>>> 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.
>>>
>>> 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>
>>> ---
>>> drivers/hwtracing/coresight/coresight-core.c | 12 ++++++------
>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>>> b/drivers/hwtracing/coresight/coresight-core.c
>>> index 88653d1c06a4..b3e3bc59c09b 100644
>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>> @@ -1382,7 +1382,7 @@ 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)
>>> @@ -1594,7 +1594,8 @@ 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;
>>> @@ -1619,8 +1620,10 @@ 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);
>>> + mutex_lock(&coresight_mutex);
>>> ret = device_register(&csdev->dev);
>>> if (ret) {
>>> + mutex_unlock(&coresight_mutex);
>>> put_device(&csdev->dev);
>>> /*
>>> * All resources are free'd explicitly via
>>> @@ -1634,6 +1637,7 @@ struct coresight_device
>>> *coresight_register(struct coresight_desc *desc)
>>> ret = etm_perf_add_symlink_sink(csdev);
>>> if (ret) {
>>> + mutex_unlock(&coresight_mutex);
>>> device_unregister(&csdev->dev);
>>> /*
>>> * As with the above, all resources are free'd
>>> @@ -1645,8 +1649,6 @@ struct coresight_device
>>> *coresight_register(struct coresight_desc *desc)
>>> }
>>> }
>>> - mutex_lock(&coresight_mutex);
>>> -
>>> ret = coresight_create_conns_sysfs_group(csdev);
>>> if (!ret)
>>> ret = coresight_fixup_device_conns(csdev);
>>> @@ -1663,8 +1665,6 @@ struct coresight_device
>>> *coresight_register(struct coresight_desc *desc)
>>> return csdev;
>>> -err_free_csdev:
>>> - kfree(csdev);
>>> err_out:
>>> /* Cleanup the connection information */
>>> coresight_release_platform_data(NULL, desc->pdata);
>>
>> Could we consolidate the unlock sequence to a single point with
>> something like this (untested):
>>
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>> b/drivers/hwtracing/coresight/coresight-core.c
>> index af00dca8d1ac..198ee140c6e6 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -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 +1661,15 @@ 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);
>> - }
>
> Apologies, this should be preserved :
>
> i.e,
> if (registered) {
> coresight_unregister(csdev);
> return ERR_PTR(ret);
> }
I will test with your changes and get back to you later.
Thanks
Jinlong Mao
>
> Thanks
> Suzuki
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] coresight: core: Fix coresight device probe failure issue
2022-03-09 2:57 ` Jinlong Mao
@ 2022-03-09 14:27 ` Jinlong Mao
0 siblings, 0 replies; 5+ messages in thread
From: Jinlong Mao @ 2022-03-09 14:27 UTC (permalink / raw)
To: Suzuki K Poulose, Mathieu Poirier, Mike Leach, Leo Yan,
Alexander Shishkin
Cc: coresight, linux-arm-kernel, linux-kernel, linux-arm-msm,
Tingwei Zhang, Yuanfang Zhang, Tao Zhang, Hao Zhang,
quic_jinlmao
Hi Suzuki,
On 3/9/2022 10:57 AM, Jinlong Mao wrote:
> Hi Suzuki,
>
> On 3/8/2022 9:36 PM, Suzuki K Poulose wrote:
>> On 08/03/2022 11:56, Suzuki K Poulose wrote:
>>> Hi Jinlong
>>>
>>> On 04/03/2022 08:23, Mao Jinlong wrote:
>>>> 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.
>>>>
>>>> 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>
>>>> ---
>>>> drivers/hwtracing/coresight/coresight-core.c | 12 ++++++------
>>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>>>> b/drivers/hwtracing/coresight/coresight-core.c
>>>> index 88653d1c06a4..b3e3bc59c09b 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>>> @@ -1382,7 +1382,7 @@ 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)
>>>> @@ -1594,7 +1594,8 @@ 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;
>>>> @@ -1619,8 +1620,10 @@ 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);
>>>> + mutex_lock(&coresight_mutex);
>>>> ret = device_register(&csdev->dev);
>>>> if (ret) {
>>>> + mutex_unlock(&coresight_mutex);
>>>> put_device(&csdev->dev);
>>>> /*
>>>> * All resources are free'd explicitly via
>>>> @@ -1634,6 +1637,7 @@ struct coresight_device
>>>> *coresight_register(struct coresight_desc *desc)
>>>> ret = etm_perf_add_symlink_sink(csdev);
>>>> if (ret) {
>>>> + mutex_unlock(&coresight_mutex);
>>>> device_unregister(&csdev->dev);
>>>> /*
>>>> * As with the above, all resources are free'd
>>>> @@ -1645,8 +1649,6 @@ struct coresight_device
>>>> *coresight_register(struct coresight_desc *desc)
>>>> }
>>>> }
>>>> - mutex_lock(&coresight_mutex);
>>>> -
>>>> ret = coresight_create_conns_sysfs_group(csdev);
>>>> if (!ret)
>>>> ret = coresight_fixup_device_conns(csdev);
>>>> @@ -1663,8 +1665,6 @@ struct coresight_device
>>>> *coresight_register(struct coresight_desc *desc)
>>>> return csdev;
>>>> -err_free_csdev:
>>>> - kfree(csdev);
>>>> err_out:
>>>> /* Cleanup the connection information */
>>>> coresight_release_platform_data(NULL, desc->pdata);
>>>
>>> Could we consolidate the unlock sequence to a single point with
>>> something like this (untested):
>>>
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>>> b/drivers/hwtracing/coresight/coresight-core.c
>>> index af00dca8d1ac..198ee140c6e6 100644
>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>> @@ -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 +1661,15 @@ 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);
>>> - }
>>
>> Apologies, this should be preserved :
>>
>> i.e,
>> if (registered) {
>> coresight_unregister(csdev);
>> return ERR_PTR(ret);
>> }
I tested with your changes.
No probe failure during reboot stress test.
I submit "[PATCH v3] coresight: core: Fix coresight device probe failure
issue".
Please help to review.
Thanks
Jinlong Mao
> I will test with your changes and get back to you later.
>
> Thanks
> Jinlong Mao
>>
>> Thanks
>> Suzuki
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-03-09 14:29 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-04 8:23 [PATCH v2] coresight: core: Fix coresight device probe failure issue Mao Jinlong
2022-03-08 11:56 ` Suzuki K Poulose
2022-03-08 13:36 ` Suzuki K Poulose
2022-03-09 2:57 ` Jinlong Mao
2022-03-09 14:27 ` Jinlong Mao
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).