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Re: [Qemu-block] [Qemu-devel] [PATCH] qcow2: avoid misaligned 64bit bswa
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH] qcow2: avoid misaligned 64bit bswap |
Date: |
Mon, 2 Nov 2015 16:46:58 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 11/02/2015 04:32 PM, John Snow wrote:
> If we create a buffer directly on the stack by using 12 bytes, there's
> no guarantee the 64bit value we want to swap will be aligned, which
> could cause errors with undefined behavior.
>
> Spotted with clang -fsanitize=undefined and observed in iotests 15, 26,
> 44, 115 and 121.
>
> Signed-off-by: John Snow <address@hidden>
> ---
> block/qcow2-refcount.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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