Messages in this thread | | | Date | Tue, 26 May 2009 14:15:52 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] devres: WARN() and return, don't crash on device_del() of uninitialized device |
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On Mon, 25 May 2009 16:53:31 +1000 Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> 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). > > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> > --- > > drivers/base/devres.c | 5 +++++ > 1 file changed, 5 insertions(+) > > --- linux-work.orig/drivers/base/devres.c 2009-05-25 16:43:46.000000000 +1000 > +++ linux-work/drivers/base/devres.c 2009-05-25 16:46:36.000000000 +1000 > @@ -428,6 +428,11 @@ int devres_release_all(struct device *de > { > unsigned long flags; > > + /* Looks like an uninitialized device structure */ > + if (dev->devres_head.next == NULL) { > + WARN(1); > + return -ENODEV; > + } > spin_lock_irqsave(&dev->devres_lock, flags); > return release_nodes(dev, dev->devres_head.next, &dev->devres_head, > flags);
This could be coded a little more neatly as:
/* Looks like an uninitialized device structure */ if (WARN_ON(dev->devres_head.next == NULL)) return -ENODEV;
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