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Date: Mon, 7 Sep 2015 00:44:10 +0200
From: Samuel Thibault <samuel.thibault@gnu.org>
Message-ID: <20150906224410.GS31785@var.home>
References: <55E73963.8080004@redhat.com>
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Subject: Re: [Qemu-devel] SLIRP segfault?
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To: John Snow <jsnow@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, qemu-devel <qemu-devel@nongnu.org>

Hello,

John Snow, le Wed 02 Sep 2015 14:01:07 -0400, a =E9crit :
> There was a downstream bug filed against qemu-kvm-2.3.1-1.fc22.x86_64
> that appeared to segfault in the AHCI code when trying to install OSX
> Yosemite.
>=20
> The debug output looked a little strange, so I asked for a new
> stack-trace on an upstream build using --enable-debug to disable
> optimizations.
>=20
> This trace came back as segfaulting in SLIRP.

This looks even stranger.

gdb) bt full
#0  0x00007ffff5ff4a2f in send () from /lib64/libpthread.so.0
No symbol table info available.
#1  0x000055555589e06d in slirp_send (so=3D0x7fffe42cc3c0, buf=3D0x7ffed8=
5747f0, len=3D0, flags=3D0) at slirp/slirp.c:900
No locals.

So the segfault would be in a send call with len=3D0 ??

I'd rather think that the segfault is actually happening in another
thread, and

thread apply all bt full

should be used to get all traces.

Samuel