On Fri, Jul 20, 2012 at 08:00:42AM -0700, Greg Kroah-Hartman wrote:
> On Fri, Jul 20, 2012 at 09:56:23AM +0300, Dan Carpenter wrote:
> > What prompted this patch is that in dma_pool_create() we call
> > dev_to_node() before checking whether "dev" is NULL. It looks like
> > there are places which call dma_pool_create() with a NULL pointer. An
> > example is in drivers/usb/gadget/amd5536udc.c.
> >
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> > Static checker fix.
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index aa7b3b4..c80e7a8d 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -714,7 +714,9 @@ int dev_set_name(struct device *dev, const char *name, ...);
> > #ifdef CONFIG_NUMA
> > static inline int dev_to_node(struct device *dev)
> > {
> > - return dev->numa_node;
> > + if (dev)
> > + return dev->numa_node;
> > + return -1;
>
> What happens if this function returns -1? Can the callers properly
> handle this?
>
Gar. Now I'm not sure any more.
-1 means no affinity and it's what the dev_to_node() returns if NUMA
is disabled. But now I think probably it's important to get the
NUMA node correct in dma_pool_create() so this isn't the right
answer.
dma_pool_create() is not correct. It has code to handle a NULL
"dev" pointer, but the dev_to_node() dereference will cause an oops
before we reach it. I'm think this is a real issue that affects a
couple drivers. Maybe those people compile without NUMA?
I'm not sure the right fix now.
regards,
dan carpenter
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