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Commit 3589972e authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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Driver core: fix race in dev_driver_string 



This patch (as1310) works around a race in dev_driver_string().  If
the device is unbound while the function is running, dev->driver might
become NULL after we test it and before we dereference it.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent c60e0504

drivers/base/core.c

+8 −1
Original line number Diff line number Diff line
@@ -56,7 +56,14 @@ static inline int device_is_not_partition(struct device *dev) 
 */

const char *dev_driver_string(const struct device *dev)

{

	return dev->driver ? dev->driver->name :

	struct device_driver *drv;



	/* dev->driver can change to NULL underneath us because of unbinding,

	 * so be careful about accessing it.  dev->bus and dev->class should

	 * never change once they are set, so they don't need special care.

	 */

	drv = ACCESS_ONCE(dev->driver);

	return drv ? drv->name :

			(dev->bus ? dev->bus->name :

			(dev->class ? dev->class->name : ""));

}