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SubjectRE: [PATCH] regmap: irq: Fix possible ZERO_SIZE_PTR pointer dereferencing error.
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> Subject: Re: [PATCH] regmap: irq: Fix possible ZERO_SIZE_PTR pointer
> dereferencing error.
>
> On Mon, May 19, 2014 at 03:13:45PM +0800, Xiubo Li wrote:
> > Since we cannot make sure the 'chip->num_regs' will always be none zero
> > from the users, and then if 'chip->num_regs' equals to zero by mistake
> > or other reasons, the kzalloc() will return ZERO_SIZE_PTR, which equals
> > to ((void *)16).
> >
> > So this patch fix this with just checking the 'chip->num_regs' before
> > calling kzalloc().
>
> Where is the actual dereference that's being protected against here?
>

Such as:
d->mask_buf = kzalloc(sizeof(unsigned int) * chip->num_regs,
GFP_KERNEL);
if (!d->mask_buf)
goto err_alloc;

And then:
d->mask_buf[irq_data->reg_offset / map->reg_stride] |= irq_data->mask;



> > This also sorts the header files in alphabetical order at the same time.
>
> No, don't do things like this. It just makes things harder to review.

Okay, I'll follow your advice.

Thanks,

BRs
Xiubo



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