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Date: Fri, 22 Mar 2013 16:50:39 -0400
From: Luiz Capitulino <lcapitulino@redhat.com>
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Subject: Re: [Qemu-devel] Abort in monitor_puts.
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To: KONRAD =?UTF-8?B?RnLDqWTDqXJpYw==?= <fred.konrad@greensocs.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, qemu-devel <qemu-devel@nongnu.org>, kraxel@redhat.com

On Fri, 22 Mar 2013 10:17:58 +0100
KONRAD Fr=C3=A9d=C3=A9ric <fred.konrad@greensocs.com> wrote:

> Hi,
>=20
> Seems there is an issue with the current git (found by toddf on IRC).
>=20
> To reproduce:
>=20
> ./qemu-system-x86_64 --monitor stdio --nographic
>=20
> and put "?" it should abort.
>=20
> Here is the backtrace:
>=20
> #0  0x00007f77cd347935 in raise () from /lib64/libc.so.6
> #1  0x00007f77cd3490e8 in abort () from /lib64/libc.so.6
> #2  0x00007f77cd3406a2 in __assert_fail_base () from /lib64/libc.so.6
> #3  0x00007f77cd340752 in __assert_fail () from /lib64/libc.so.6
> #4  0x00007f77d1c1f226 in monitor_puts (mon=3D<optimized out>,
>      str=3D<optimized out>) at=20

Yes, it's easy to reproduce. Bisect says:

f628926bb423fa8a7e0b114511400ea9df38b76a is the first bad commit
commit f628926bb423fa8a7e0b114511400ea9df38b76a
Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Tue Mar 19 10:57:56 2013 +0100

    fix monitor
   =20
    chardev flow control broke monitor, fix it by adding watch support.
   =20
    Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

My impression is that monitor_puts() in being called in parallel.