From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39914) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQFvn-0004vm-98 for qemu-devel@nongnu.org; Fri, 14 Aug 2015 10:26:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZQFvk-0007bs-36 for qemu-devel@nongnu.org; Fri, 14 Aug 2015 10:26:03 -0400 Received: from indium.canonical.com ([91.189.90.7]:37192) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZQFvj-0007bn-U3 for qemu-devel@nongnu.org; Fri, 14 Aug 2015 10:26:00 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.76 #1 (Debian)) id 1ZQFvi-0006B6-C0 for ; Fri, 14 Aug 2015 14:25:58 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 9D57B2E8239 for ; Fri, 14 Aug 2015 14:25:53 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Fri, 14 Aug 2015 14:17:29 -0000 From: Daniel Berrange <1484925@bugs.launchpad.net> Sender: bounces@canonical.com References: <20150814122340.5606.46979.malonedeb@gac.canonical.com> Message-Id: <20150814141729.19929.27457.malone@wampee.canonical.com> Errors-To: bounces@canonical.com Subject: [Qemu-devel] [Bug 1484925] Re: Segfault with custom vnc client Reply-To: Bug 1484925 <1484925@bugs.launchpad.net> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Can you attach GDB to your qemu-dm process and attempt to capture a full stack trace when it crashes (ie thread apply all backtrace) -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1484925 Title: Segfault with custom vnc client Status in QEMU: New Bug description: Hey, I'm using Citrix XenServer 6.5. I worte a script that uses noVNC to connect to the rfb console via xapi. When I use GRML and try to boot it, the QEMU process segfaults and kills my VM. This happens when the screen resizes and the kernel is loading: recvfrom(3, "\3\1\0\0\0\0\2\200\1\220\3\0\2\200\0\0\0P\1\220", 4096, 0, N= ULL, NULL) =3D 20 --- SIGSEGV {si_signo=3DSIGSEGV, si_code=3DSEGV_MAPERR, si_addr=3D0xb2800= 0} --- I can see in the child process the following message, right before the pa= rent Segfaults: read(4, "cirrus: blanking the screen line_offset=3D0 height=3D480\n", 53)= =3D 53 This issue only happens, when I have my custom php/novnc-client connected. I also tried the nodejs/novnc package from xen-orchestra - same result. Using the stock client from Citrix XenCenter it works just fine. So I think it is related to noVNC. I hope this is just a bug and not exploitable to force a VM to crash or execute code. XenServer launches the qemu with the following command line: qemu-dm-25 --syslog -d 25 -m 2048 -boot dc -serial pty -vcpus 1 -videoram 4 -vncunused -k en-us -vnc 127.0.0.1:1 -usb -usbdevice tablet -net nic,vlan=3D0,macaddr=3D8a:43:e2:b1:57:df,model=3Drtl8139 -net tap,vlan=3D0,bridge=3Dxenbr0,ifname=3Dtap25.0 -acpi -monitor pty XenServer 6.5 is using the following version: # /usr/lib64/xen/bin/qemu-dm -help QEMU PC emulator version 0.10.2, Copyright (c) 2003-2008 Fabrice Bellard Greetings Uli St=C3=A4rk To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1484925/+subscriptions