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From: Peter Maydell <peter.maydell@linaro.org>
Date: Mon, 5 Nov 2018 14:45:02 +0000
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Content-Type: text/plain; charset="UTF-8"
Subject: Re: [Qemu-devel] [PATCH] block/vdi: Don't take address of fields in
 packed structs
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To: Kevin Wolf <kwolf@redhat.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>, "patches@linaro.org" <patches@linaro.org>, Stefan Weil <sw@weilnetz.de>, Max Reitz <mreitz@redhat.com>, Qemu-block <qemu-block@nongnu.org>

On 17 October 2018 at 15:55, Kevin Wolf <kwolf@redhat.com> wrote:
> Am 16.10.2018 um 19:25 hat Peter Maydell geschrieben:
>> Taking the address of a field in a packed struct is a bad idea, because
>> it might not be actually aligned enough for that pointer type (and
>> thus cause a crash on dereference on some host architectures). Newer
>> versions of clang warn about this. Avoid the bug by not using the
>> "modify in place" byte swapping functions.
>>
>> There are a few places where the in-place swap function is
>> used on something other than a packed struct field; we convert
>> those anyway, for consistency.
>>
>> Patch produced with scripts/coccinelle/inplace-byteswaps.cocci.
>>
>> There are other places where we take the address of a packed member
>> in this file for other purposes than passing it to a byteswap
>> function (all the calls to qemu_uuid_*()); we leave those for now.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>
> Thanks, applied to the block branch.

This also hasn't made it into master.

thanks
-- PMM