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device-core: Ensure drvdata = NULL when no driver is bound

1) drvdata is for a driver to store a pointer to driver specific data
2) If no driver is bound, there is no driver specific data associated with
   the device
3) Thus logically drvdata should be NULL if no driver is bound.

But many drivers don't clear drvdata on device_release, or set drvdata
early on in probe and leave it set on probe error. Both of which results
in a dangling pointer in drvdata.

This patch enforce for drvdata to be NULL after device_release or on probe
failure.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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1 parent b02f8be commit 0998d0631001288a5974afc0b2a5f568bcdecb4d @jwrdegoede jwrdegoede committed with gregkh May 22, 2012
Showing with 2 additions and 0 deletions.
  1. +2 −0 drivers/base/dd.c
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@@ -283,6 +283,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
devres_release_all(dev);
driver_sysfs_remove(dev);
dev->driver = NULL;
+ dev_set_drvdata(dev, NULL);
if (ret == -EPROBE_DEFER) {
/* Driver requested deferred probing */
@@ -487,6 +488,7 @@ static void __device_release_driver(struct device *dev)
drv->remove(dev);
devres_release_all(dev);
dev->driver = NULL;
+ dev_set_drvdata(dev, NULL);
klist_remove(&dev->p->knode_driver);
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,

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