[PATCH 16/44] driver-core: fix race between device_register and driver_register

Greg Kroah-Hartman
2011-05-20T00:11:36Z

From: Sebastian Ott <sebott@linux.vnet.ibm.com>

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
device.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/dd.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index da57ee9..7e9219b 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -245,6 +245,10 @@ int device_attach(struct device *dev)

device_lock(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);
pm_runtime_put_sync(dev);
}
+out_unlock:
device_unlock(dev);
return ret;
}
--
1.7.4.2