Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | Re: [PATCH 2/4] ARM: common/locomo: remove NO_IRQ check | Date | Tue, 06 Sep 2016 16:50:02 +0200 |
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On Tuesday, September 6, 2016 3:21:44 PM CEST Russell King - ARM Linux wrote: > On Tue, Sep 06, 2016 at 03:53:28PM +0200, Arnd Bergmann wrote: > > Since commit 489447380a29 ("[PATCH] handle errors returned by > > platform_get_irq*()") ten years ago, the locomo driver refuses to > > work without an interrupt line passed in its resources, so the > > check for NO_IRQ is unnecessary. > > This description is inaccurate and misleading (it looks like it was > cut'n'pasted from patch 1.) > > platform_get_irq() has nothing to do with your change, as your change > is more about the irq_base value passed through platform data, and > not through IRQ resources.
It was copied, but this part refers to this hunk
irq = platform_get_irq(dev, 0); if (irq < 0) return -ENXIO;
from locomo_probe that was changed in the same patch as the on in sa1111.c
> > We still check the irq_base argument for NO_IRQ, but as both
where the irq_base comes in.
I'll try to reword this to make it clearer.
> > @@ -387,7 +389,7 @@ __locomo_probe(struct device *me, struct resource *mem, int irq) > > > > lchip->phys = mem->start; > > lchip->irq = irq; > > - lchip->irq_base = (pdata) ? pdata->irq_base : NO_IRQ; > > + lchip->irq_base = pdata->irq_base; > > This removes a NULL pointer check. Before this change, a NULL pdata > would be accepted and would lead to the interrupts not being setup. > After this change, it results in a NULL pointer deference. > > Thankfully, both collie and poodle supply platform data, and are the > only providers of the locomo device.
Right, that is what I tried to say above. With the check I've added in __locomo_probe, it would actually get the NULL pointer dereference earlier than this line. I'll add back that check earlier in the function and return an error in that case.
Arnd
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