From: David Miller <davem@davemloft.net>
To: cmetcalf@tilera.com
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kaber@trash.net
Subject: Re: [PATCH] ip_options_compile: properly handle unaligned pointer
Date: Tue, 31 May 2011 15:13:21 -0700 (PDT) [thread overview]
Message-ID: <20110531.151321.494228226.davem@davemloft.net> (raw)
In-Reply-To: <201105292112.p4TLC6cN017178@farm-0002.internal.tilera.com>
From: Chris Metcalf <cmetcalf@tilera.com>
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@tilera.com>
Applied, thanks Chris.
prev parent reply other threads:[~2011-05-31 22:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-29 20:55 [PATCH] ip_options_compile: properly handle unaligned pointer Chris Metcalf
2011-05-31 22:13 ` David Miller [this message]
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