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authorAlan Stern <stern@rowland.harvard.edu>2007-11-16 11:57:28 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2008-01-24 20:40:35 -0800
commitef2c51746dc89c2326ce522f8fb8a57695780e75 (patch)
tree80aacaea0a3124713f4cff5b14e5c98c97dd6b9b
parentc8e90d822bff3e0502d004facedb05859f98055f (diff)
Driver core: fix race in __device_release_driver
This patch (as1013) was suggested by David Woodhouse; it fixes a race in the driver core. If a device is unregistered at the same time as its driver is unloaded, the driver's code pages may be unmapped while the remove method is still running. The calls to get_driver() and put_driver() were intended to prevent this, but they don't work if the driver's module count has already dropped to 0. Instead, the patch keeps the device on the driver's list until after the remove method has returned. This forces the necessary synchronization to occur. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/base/dd.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 54922647522..b0726eb6405 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -289,11 +289,10 @@ static void __device_release_driver(struct device * dev)
{
struct device_driver * drv;
- drv = get_driver(dev->driver);
+ drv = dev->driver;
if (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->p->bus_notifier,
@@ -306,7 +305,7 @@ static void __device_release_driver(struct device * dev)
drv->remove(dev);
devres_release_all(dev);
dev->driver = NULL;
- put_driver(drv);
+ klist_remove(&dev->knode_driver);
}
}