On 30 Mar 2016, at 14:23, Christophe TREFOIS = <christophe.trefois@uni.lu> wrote: =20 Hi Kevin, =20 Ok thanks for the feedback. =20 Do you have experience with kernel panics and more specifically how to = get any meaningful message if this is happening? =20 According to syslog on the guest, at least after reboot, there's no = information that something went wrong. =20 Since this seems to leave the qemu world, I'm now not sure where to = ask for support in this :( =20 Kind regards, =20 -- Christophe=20 Sent from my iPhone =20
On 30 Mar 2016, at 14:14, Kevin Wolf <kwolf@redhat.com> wrote: =20 Hi Christophe, =20 Am 30.03.2016 um 13:45 hat Christophe TREFOIS geschrieben:
Another host went down, so I have to prepare info for this one. =20 I could not SSH to it anymore. Console would show login screen, but no keystrokes were registered. =20 I could =E2=80=9Csuspend=E2=80=9D the VM and =E2=80=9Crun=E2=80=9D = it, but still can=E2=80=99t SSH to it. Before suspension, all QEMU threads were around 0%, after resuming, = 3 of them hover at 100%. =20 Attached you could find the gdb, core dump, and other logs. =20 Logs: https://dl.dropboxusercontent.com/u/63261/ubuntu2-logs.tar.gz =20 Core Dump: = https://dl.dropboxusercontent.com/u/63261/core-ubuntu2.tar.gz =20 Is there anything else we could provide? =20 This sounds much like it's not qemu that hangs (because then stopping and resuming wouldn't work any more), but just the guest OS that is running inside the VM. =20 We've had cases before where qemu was reported to hang with 100% CPU usage and in the end it turned out that the guest kernel had =
Can you check whether a guest kernel crash could be the cause? If =
--Apple-Mail=_A6E314DB-0BAC-4676-B749-587BFB466697 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hi, Just to give a small update. It seems that when installing the willy-lts-kernel backport package on = 14.04, the VMs stopped getting stuck. We have now been running 6 weeks without a single VM crashing. Before, we had 1-2 per day. Maybe it will be useful to somebody. Kind regards, =E2=80=94 Christophe =20 panicked. this
is reproducible, maybe the easiest way would be to attach a serial console to the VM and let the kernel print its messages there. =20 Kevin
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