From 0d3e5a2e39b6ba2974e9e7c2a429018c45de8e76 Mon Sep 17 00:00:00 2001 From: Patrick Mochel Date: Tue, 5 Apr 2005 23:46:33 -0700 Subject: [PATCH] Driver Core: fix bk-driver-core kills ppc64 There's no check to see if the device is already bound to a driver, which could do bad things. The first thing to go wrong is that it will try to match a driver with a device already bound to one. In some cases (it appears with USB with drivers/usb/core/usb.c::usb_match_id()), some drivers will match a device based on the class type, so it would be common (especially for HID devices) to match a device that is already bound. The fun comes when ->probe() is called, it fails, then driver_probe_device() does this: dev->driver = NULL; Later on, that pointer could be be dereferenced without checking and cause hell to break loose. This problem could be nasty. It's very hardware dependent, since some devices could have a different set of matching qualifiers than others. Now, I don't quite see exactly where/how you were getting that crash. You're dereferencing bad memory, but I'm not sure which pointer was bad and where it came from, but it could have come from a couple of different places. The patch below will hopefully fix it all up for you. It's against 2.6.12-rc2-mm1, and does the following: - Move logic to driver_probe_device() and comments uncommon returns: 1 - If device is bound 0 - If device not bound, and no error error - If there was an error. - Move locking to caller of that function, since we want to lock a device for the entire time we're trying to bind it to a driver (to prevent against a driver being loaded at the same time). - Update __device_attach() and __driver_attach() to do that locking. - Check if device is already bound in __driver_attach() - Update the converse device_release_driver() so it locks the device around all of the operations. - Mark driver_probe_device() as static and remove export. It's an internal function, it should stay that way, and there are no other callers. If there is ever a need to export it, we can audit it as necessary. Signed-off-by: Andrew Morton --- include/linux/device.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/device.h b/include/linux/device.h index 43249260cd1c..91aac349b9a7 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -325,7 +325,6 @@ extern int device_for_each_child(struct device *, void *, * Manual binding of a device to driver. See drivers/base/bus.c * for information on use. */ -extern int driver_probe_device(struct device_driver * drv, struct device * dev); extern void device_bind_driver(struct device * dev); extern void device_release_driver(struct device * dev); extern int device_attach(struct device * dev); -- cgit v1.2.3