On Tue, Aug 25, 2026 at 09:47:17AM +0800, yingchao wrote:

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 2bfdd7b45e49..d0e7e4720e46 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -1210,8 +1210,14 @@ static int cscfg_create_device(void) dev->init_name = "cs_system_cfg"; err = device_register(dev);

• if (err)

• if (err) {

• /* put_device() triggers cscfg_dev_release() which takes
  

•  * cscfg_mutex, so drop the lock first to avoid deadlocking.
  

•  */
  

• mutex_unlock(&cscfg_mutex);
  

  put_device(dev);

• return err;
  

• }

As module init and exit are serialized by the kernel, I don't think we need the mutex to protect the allocation and freeing of cscfg_mgr.

The mutex should only be used for exclusively access cscfg_mgr. So how about the change below?

---8<---

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 2bfdd7b45e49..2dd0b29f44e4 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -1173,27 +1173,21 @@ struct device *cscfg_device(void) /* Must have a release function or the kernel will complain on module unload */ static void cscfg_dev_release(struct device *dev) { - mutex_lock(&cscfg_mutex); kfree(cscfg_mgr); cscfg_mgr = NULL; - mutex_unlock(&cscfg_mutex); }

/* a device is needed to "own" some kernel elements such as sysfs entries. */ static int cscfg_create_device(void) { struct device *dev; - int err = -ENOMEM; - - mutex_lock(&cscfg_mutex); - if (cscfg_mgr) { - err = -EINVAL; - goto create_dev_exit_unlock; - } + int err;

cscfg_mgr = kzalloc_obj(struct cscfg_manager); if (!cscfg_mgr) - goto create_dev_exit_unlock; + return -ENOMEM; + + mutex_lock(&cscfg_mutex);

/* initialise the cscfg_mgr structure */ INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list); @@ -1204,6 +1198,8 @@ static int cscfg_create_device(void) cscfg_mgr->load_state = CSCFG_NONE; raw_spin_lock_init(&cscfg_mgr->sysfs_store_lock);

+ mutex_unlock(&cscfg_mutex); + /* setup the device */ dev = cscfg_device(); dev->release = cscfg_dev_release; @@ -1213,8 +1209,6 @@ static int cscfg_create_device(void) if (err) put_device(dev);

-create_dev_exit_unlock: - mutex_unlock(&cscfg_mutex); return err; }