[PATCH] driver-core: fix race between device_register anddriver_register

From: Sebastian Ott
Date: Tue Apr 12 2011 - 13:05:52 EST

When a device is registered to a bus it will be a) added to the list
of devices of the bus and b) bind to a driver (if one matches). As a
result of a driver being registered at this bus between a) and b) this
device could already be bound to a driver. This leads to a warning
and incorrect refcounting.
To fix this add a check to device_attach to identify an already bound

Signed-off-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
drivers/base/dd.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -245,6 +245,10 @@ int device_attach(struct device *dev)

if (dev->driver) {
+ if (klist_node_attached(&dev->p->knode_driver)) {
+ ret = 1;
+ goto out_unlock;
+ }
ret = device_bind_driver(dev);
if (ret == 0)
ret = 1;
@@ -257,6 +261,7 @@ int device_attach(struct device *dev)
ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
return ret;
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