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Date: Sat, 17 Mar 2012 08:10:58 +0100
From: Stefan Weil <sw@weilnetz.de>
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Subject: Re: [Qemu-devel] VDI patches (was: buildbot failure in qemu on
	block_i386_debian_6_0)
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To: Paolo Bonzini <pbonzini@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Alexander Graf <agraf@suse.de>
Cc: gollub@b1-systems.de, qemu-devel@nongnu.org, lcapitulino@redhat.com

Am 17.03.2012 04:11, schrieb qemu@buildbot.b1-systems.de:
> The Buildbot has detected a new failure on builder 
> block_i386_debian_6_0 while building qemu.
> Full details are available at:
> http://buildbot.b1-systems.de/qemu/builders/block_i386_debian_6_0/builds/215
>
> Buildbot URL: http://buildbot.b1-systems.de/qemu/
>
> Buildslave for this Build: yuzuki
>
> Build Reason: The Nightly scheduler named 'nightly_block' triggered 
> this build
> Build Source Stamp: [branch block] HEAD
> Blamelist:
>
> BUILD FAILED: failed compile
>
> sincerely,
> -The Buildbot

Hi Kevin, hi Paolo,

the build failure is caused by the vdi changes: some versions of gcc
detect uninitialized local variables (my gcc 4.4.5 does not).

I don't think that it's really an error because the code is guarded
by the local variable 'block', but not all compilers are clever enough,
so it should be fixed.

It can be fixed by modifying commit af93911fd45f4de34ca2d5813905e2cf43675c98
(vdi: move aiocb fields to locals) like that:

--- a/block/vdi.c
+++ b/block/vdi.c
@@ -519,8 +519,8 @@ static int vdi_co_write(BlockDriverState *bs,
      uint32_t block_index;
      uint32_t sector_in_block;
      uint32_t n_sectors;
-    uint32_t bmap_first;
-    uint32_t bmap_last;
+    uint32_t bmap_first = VDI_UNALLOCATED;
+    uint32_t bmap_last = VDI_UNALLOCATED;
      uint8_t *block = NULL;
      int ret = 0;

Regards,
Stefan W.