sysdev: detect multiple driver registrations (da009f39) · Commits · 戴 / test

I've just found how easy it is to accidentally register a sysdev_driver for two different classes. When this happens, bad things happen as the sysdev_driver structure keeps has the list entry for the driver registration. The following patch makes a WARN_ON() if this happens, although I think BUG_ON or returning -EAGAIN could also be valid responses to this. Signed-off-by:

Ben Dooks <ben@fluff.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/sys.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -167,6 +167,22 @@ int sysdev_driver_register(struct sysdev_class cls, struct sysdev_driver drv)
		{
		int err = 0;

		if (!cls) {
		printk(KERN_WARNING "sysdev: invalid class passed to "
		"sysdev_driver_register!\n");
		WARN_ON(1);
		return -EINVAL;
		}

		/* Check whether this driver has already been added to a class. */
		if ((drv->entry.next != drv->entry.prev) \|\|
		(drv->entry.next != NULL)) {
		printk(KERN_WARNING "sysdev: class %s: driver (%p) has already"
		" been registered to a class, something is wrong, but "
		"will forge on!\n", cls->name, drv);
		WARN_ON(1);
		}

		mutex_lock(&sysdev_drivers_lock);
		if (cls && kset_get(&cls->kset)) {
		list_add_tail(&drv->entry, &cls->drivers);

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