Re: Khubd calls disconnect() after driver module unloaded

On Tue, 2007-11-13 at 19:16 -0500, David Woodhouse wrote:
> It seems that driver_detach() doesn't find any devices to detach _from_
> (there were printks there for when it called a remove function, _and_
> for when it didn't because the driver didn't match).
> 
> drv->klist_devices.k_list is empty already.

... because we removed the device from the driver's list _before_
calling the driver's ->remove() function. And although we're holding a
refcount on the driver, that doesn't really help because the driver
module is already in the process of being unloaded.

This patch 'fixes' it. I've no idea if it's the right fix though, having
not paid much attention to the locking issues here... 

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index b0088b0..90ab311 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -301,7 +301,6 @@ static void __device_release_driver(struct device * dev)
 		get_driver(drv);
 		driver_sysfs_remove(dev);
 		sysfs_remove_link(&dev->kobj, "driver");
-		klist_remove(&dev->knode_driver);
 
 		if (dev->bus)
 			blocking_notifier_call_chain(&dev->bus->bus_notifier,
@@ -314,6 +313,7 @@ static void __device_release_driver(struct device * dev)
 			drv->remove(dev);
 		devres_release_all(dev);
 		dev->driver = NULL;
+		klist_remove(&dev->knode_driver);
 		put_driver(drv);
 	}
 }

Another fix might be for driver_detach() to actually wait until the use
count on the driver becomes zero.

-- 
dwmw2


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