Re: [PATCH] ip_options_compile: properly handle unaligned pointer

From: David Miller
Date: Tue May 31 2011 - 18:14:36 EST


From: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Date: Sun, 29 May 2011 16:55:44 -0400

> The current code takes an unaligned pointer and does htonl() on it to
> make it big-endian, then does a memcpy(). The problem is that the
> compiler decides that since the pointer is to a __be32, it is legal
> to optimize the copy into a processor word store. However, on an
> architecture that does not handled unaligned writes in kernel space,
> this produces an unaligned exception fault.
>
> The solution is to track the pointer as a "char *" (which removes a bunch
> of unpleasant casts in any case), and then just use put_unaligned_be32()
> to write the value to memory.
>
> Signed-off-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>

Applied, thanks Chris.
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