devres: WARN() and return, don't crash on device_del() of uninitialized device
authorBenjamin Herrenschmidt <benh@kernel.crashing.org>
Wed, 10 Jun 2009 19:43:02 +0000 (12:43 -0700)
committerGreg Kroah-Hartman <gregkh@suse.de>
Sun, 12 Jul 2009 20:02:09 +0000 (13:02 -0700)
I just debugged an obscure crash caused by a device_del() of a all NULL'd
out struct device (in usb-serial) and found that a patch like this one would
have saved me time (in addition to improved chances of a bug report from
users hitting similar driver bugs).

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/base/devres.c

index e8beb8e5b6264232dbfc0ea2dc7ae95d76f5af64..05dd307e8f024038bfe6e9d762e3dff1dd6281ee 100644 (file)
@@ -428,6 +428,9 @@ int devres_release_all(struct device *dev)
 {
        unsigned long flags;
 
+       /* Looks like an uninitialized device structure */
+       if (WARN_ON(dev->devres_head.next == NULL))
+               return -ENODEV;
        spin_lock_irqsave(&dev->devres_lock, flags);
        return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
                             flags);