[PATCH 0/1] Fix issue with module unload and CTI cleanup

[PATCH 0/1] Fix issue with module unload and CTI cleanup

[Mike Leach]

In the proposed Coresight module set v5 [1] from Tingwei, unloading the
ETM module before the CTI module will crash on unload of the CTI module
due to the cleanup callback from Coresight to the CTI module not working
correctly in clearing sysfs callbacks.

Patch fixes this issue. Applies on [1].

Tingwei - could you consider adding this to your set for v6?

[1] https://lists.linaro.org/pipermail/coresight/2020-July/004349.html

Mike Leach (1):
  coresight: cti: Fix bug clearing sysfs links on callback

 drivers/hwtracing/coresight/coresight-core.c     | 4 ++--
 drivers/hwtracing/coresight/coresight-cti-core.c | 3 +--
 2 files changed, 3 insertions(+), 4 deletions(-)

-- 
2.17.1


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[PATCH 1/1] coresight: cti: Fix bug clearing sysfs links on callback

[Mike Leach]

During module unload, a coresight driver module will call back into
the CTI driver to remove any links between the two devices.

The current code has 2 issues:-
1) in the CTI driver the matching code is matching to the wrong device
so misses all the links.
2) The callback is called too late in the unload process resulting in a
crash.

This fixes both the issues.

Fixes: 177af8285b59 (coresight: cti: Enable CTI associated with devices)
Reported-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
 drivers/hwtracing/coresight/coresight-core.c     | 4 ++--
 drivers/hwtracing/coresight/coresight-cti-core.c | 3 +--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index a11288fbb160..c849c2afbcfb 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1254,8 +1254,6 @@ static void coresight_device_release(struct device *dev)
 {
 	struct coresight_device *csdev = to_coresight_device(dev);
 
-	if (cti_assoc_ops && cti_assoc_ops->remove)
-		cti_assoc_ops->remove(csdev);
 	fwnode_handle_put(csdev->dev.fwnode);
 	kfree(csdev->refcnt);
 	kfree(csdev);
@@ -1580,6 +1578,8 @@ void coresight_unregister(struct coresight_device *csdev)
 {
 	etm_perf_del_symlink_sink(csdev);
 	/* Remove references of that device in the topology */
+	if (cti_assoc_ops && cti_assoc_ops->remove)
+		cti_assoc_ops->remove(csdev);
 	coresight_remove_conns(csdev);
 	coresight_clear_default_sink(csdev);
 	coresight_release_platform_data(csdev, csdev->pdata);
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index 255e914b21b5..c5a4213d6623 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -502,7 +502,6 @@ static bool cti_add_sysfs_link(struct cti_drvdata *drvdata,
 	link_info.orig_name = tc->con_dev_name;
 	link_info.target = tc->con_dev;
 	link_info.target_name = dev_name(&drvdata->csdev->dev);
-
 	link_err = coresight_add_sysfs_link(&link_info);
 	if (link_err)
 		dev_warn(&drvdata->csdev->dev,
@@ -608,7 +607,7 @@ void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
 		ctidrv = csdev_to_cti_drvdata(csdev->ect_dev);
 		ctidev = &ctidrv->ctidev;
 		list_for_each_entry(tc, &ctidev->trig_cons, node) {
-			if (tc->con_dev == csdev->ect_dev) {
+			if (tc->con_dev == csdev) {
 				cti_remove_sysfs_link(ctidrv, tc);
 				tc->con_dev = NULL;
 				break;
-- 
2.17.1


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Re: [PATCH 0/1] Fix issue with module unload and CTI cleanup

[Tingwei Zhang]

On Thu, Jul 30, 2020 at 03:52:32AM +0800, Mike Leach wrote:
> In the proposed Coresight module set v5 [1] from Tingwei, unloading the
> ETM module before the CTI module will crash on unload of the CTI module
> due to the cleanup callback from Coresight to the CTI module not working
> correctly in clearing sysfs callbacks.
> 
> Patch fixes this issue. Applies on [1].
> 
> Tingwei - could you consider adding this to your set for v6?

Sure, Mike.  I'll pick this change into v6.

Thanks, Tingwei
> 
> [1] https://lists.linaro.org/pipermail/coresight/2020-July/004349.html
> 
> Mike Leach (1):
>   coresight: cti: Fix bug clearing sysfs links on callback
> 
>  drivers/hwtracing/coresight/coresight-core.c     | 4 ++--
>  drivers/hwtracing/coresight/coresight-cti-core.c | 3 +--
>  2 files changed, 3 insertions(+), 4 deletions(-)
> 
> -- 
> 2.17.1
> 

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