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From: Markus Armbruster <armbru@redhat.com>
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Date: Mon, 21 Mar 2016 12:52:33 +0100
In-Reply-To: <CAFEAcA-WK7H0=KsEFXr05Kd79+YiudBQoODQJz5-m1VFcHQs1A@mail.gmail.com>
	(Peter Maydell's message of "Mon, 21 Mar 2016 10:18:15 +0000")
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Subject: Re: [Qemu-devel] [PULL 00/40] ivshmem: Fixes, cleanups,
	device model split
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: QEMU Developers <qemu-devel@nongnu.org>

Peter Maydell <peter.maydell@linaro.org> writes:

> On 21 March 2016 at 10:05, Markus Armbruster <armbru@redhat.com> wrote:
>> Peter Maydell <peter.maydell@linaro.org> writes:
>>> Also some new clang ubsan warnings on x86 Linux:
>>> GTESTER check-qtest-i386
>>> [deleted existing warnings about slirp code]
>>> /home/petmay01/linaro/qemu-for-merges/hw/pci/pci.c:166:23: runtime
>>> error: shift exponent -1 is negative
>>> /home/petmay01/linaro/qemu-for-merges/hw/pci/pci.c:171:24: runtime
>>> error: shift exponent -1 is negative
>>> /home/petmay01/linaro/qemu-for-merges/hw/pci/pci.c:172:24: runtime
>>> error: shift exponent -1 is negative
>>
>> Stack backtrace?  If it's not too much trouble...
>
> Sorry, too painful -- this version of clang doesn't support
> the UBSAN_OPTIONS environment variable to request a backtrace
> at runtime and I can't remember the rune to connect gdb to
> the qemu under a qtest test, which is what I'd need to do if
> I rebuilt everything with the trap-on-error flag.
>
> The issues are all provoked by the i386/ivshmem/single test.

No worries, I reproduced it locally.