Re: [PATCH] gpio: null pointer dereference in error handling in gpiolib.c

[Linus Walleij]

On Fri, Aug 30, 2013 at 7:10 AM, Frank Rowand
<frank.rowand@xxxxxxxxxxxxxx> wrote:

> Avoid calling desc_to_gpio() if desc->chip is NULL, as this will
> cause a kernel panic.
>
> In the code above the calls, there is a test for !chip, which
> comes to the 'fail' label if true. In this case, the code
> panics, since desc_to_gpio() uses desc->chip to look up the
> gpio number.
>
> An RFC patch that explained the cause of one example of panic when
> desc->chip is NULL and fixed that example
> (http://lkml.indiana.edu/hypermail/linux/kernel/1308.3/01473.html)
> was accepted.  This patch fixes the remaining locations which have
> the same problem.
>
> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxxxxx>

Hm it appears Alexandre has another idea on how it should be
fixed, but he was in a hurry and didn't provide a proper patch.

Let me cook something up so we can see of we can get
this right.

Yours,
Linus Walleij
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