From b15f0fb657e040401d875d11ae13b269af8a16e0 Mon Sep 17 00:00:00 2001 From: Mathieu Poirier Date: Tue, 2 Feb 2016 14:14:00 -0700 Subject: coresight: removing bind/unbind options from sysfs The coresight drivers have absolutely no control over bind and unbind operations triggered from sysfs. The operations simply can't be cancelled or denied event when one or several tracing sessions are under way. Since the memory associated to individual device is invariably freed, the end result is a kernel crash when the path from source to sink is travelled again as demonstrated here[1]. One solution could be to keep track of all the path (i.e tracing session) that get created and iterate through the elements of those path looking for the coresight device that is being removed. This proposition doesn't scale well since there is no upper bound on the amount of concurrent trace session that can be created. With the above in mind, this patch prevent devices from being unbounded from their driver by using the driver->suppress_bind_attr option. That way trace sessions can be managed without fearing to loose devices. Since device can't be removed anymore the xyz_remove() functions found in each driver is also removed. [1]. http://www.spinics.net/lists/arm-kernel/msg474952.html Reported-by: Rabin Vincent Signed-off-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-tpiu.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'drivers/hwtracing/coresight/coresight-tpiu.c') diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c index 7214efd10db5..ca50e73d9df7 100644 --- a/drivers/hwtracing/coresight/coresight-tpiu.c +++ b/drivers/hwtracing/coresight/coresight-tpiu.c @@ -172,14 +172,6 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id) return 0; } -static int tpiu_remove(struct amba_device *adev) -{ - struct tpiu_drvdata *drvdata = amba_get_drvdata(adev); - - coresight_unregister(drvdata->csdev); - return 0; -} - #ifdef CONFIG_PM static int tpiu_runtime_suspend(struct device *dev) { @@ -223,9 +215,9 @@ static struct amba_driver tpiu_driver = { .name = "coresight-tpiu", .owner = THIS_MODULE, .pm = &tpiu_dev_pm_ops, + .suppress_bind_attrs = true, }, .probe = tpiu_probe, - .remove = tpiu_remove, .id_table = tpiu_ids, }; -- cgit v1.2.3-59-g8ed1b