Bugs item #2351676, was opened at 2008-11-26 12:59
Message generated for change (Comment added) made by c_jones
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Chris Jones (c_jones)
Assigned to: Nobody/Anonymous (nobody)
Summary: Guests hang periodically on Ubuntu-8.10
Initial Comment:
I'm seeing periodic hangs on my guests. I've been unable so far to find a
trigger - they always boot fine, but after anywhere from 10 minutes to 24 hours
they eventually hang completely.
My setup:
* AMD Athlon X2 4850e (2500 MHz dual core)
* 4Gig memory
* Ubuntu 8.10 server, 64-bit
* KVMs tried:
: kvm-72 (shipped with ubuntu)
: kvm-79 (built myself, --patched-kernel option)
* Kernels tried:
: 2.6.27.7 (kernel.org, self built)
: 2.6.27-7-server from Ubuntu 8.10 distribution
In guests
* Ubuntu 8.10 server, 64-bit (virtual machine install)
* kernel 2.6.27-7-server from Ubuntu 8.10
I'm running the guests like:
sudo /usr/local/bin/qemu-system-x86_64 \
-daemonize \
-no-kvm-irqchip \
-hda Imgs/ndev_root.img \
-m 1024 \
-cdrom ISOs/ubuntu-8.10-server-amd64.iso \
-vnc :4 \
-net nic,macaddr=DE:AD:BE:EF:04:04,model=e1000 \
-net tap,ifname=tap4,script=/home/chris/kvm/qemu-ifup.sh
The problem does not happen if I use -no-kvm.
I've tried some other options that have no effect:
-no-kvm-pit
-no-acpi
The disk images are raw format.
When the guests hang, I cannot ping them, and the vnc console us hung. The
qemu monitor is still accessible, and the guests recover if I issue a
system_reset command from the monitor. However, often, the console will not
take keyboard after doing so.
When the guest is hung, kvm_stat shows all 0s for the counters:
efer_relo exits fpu_reloa halt_exit halt_wake host_stat hypercall
+insn_emul insn_emul invlpg io_exits irq_exits irq_windo largepage
+mmio_exit mmu_cache mmu_flood mmu_pde_z mmu_pte_u mmu_pte_w mmu_recyc
+mmu_shado nmi_windo pf_fixed pf_guest remote_tl request_i signal_ex
+tlb_flush
> 0 0 0 0 0 0 0
+0 0 0 0 0 0 0 0
+0 0 0 0 0 0 0 0
+0 0 0 0 0 0
gdb shows two threads - both waiting:
c(gdb) info threads
2 Thread 0x414f1950 (LWP 422) 0x00007f36f07a03e1 in sigtimedwait ()
from /lib/libc.so.6
1 Thread 0x7f36f1f306e0 (LWP 414) 0x00007f36f084b482 in select ()
from /lib/libc.so.6
(gdb) thread 1
[Switching to thread 1 (Thread 0x7f36f1f306e0 (LWP 414))]#0 0x00007f36f084b482
+in select () from /lib/libc.so.6
(gdb) bt
#0 0x00007f36f084b482 in select () from /lib/libc.so.6
#1 0x00000000004094cb in main_loop_wait (timeout=0)
at /home/chris/pkgs/kvm/kvm-79/qemu/vl.c:4719
#2 0x000000000050a7ea in kvm_main_loop ()
at /home/chris/pkgs/kvm/kvm-79/qemu/qemu-kvm.c:619
#3 0x000000000040fafc in main (argc=<value optimized out>,
argv=0x7ffff9f41948) at /home/chris/pkgs/kvm/kvm-79/qemu/vl.c:4871
(gdb) thread 2
[Switching to thread 2 (Thread 0x414f1950 (LWP 422))]#0 0x00007f36f07a03e1 in
+sigtimedwait () from /lib/libc.so.6
(gdb) bt
#0 0x00007f36f07a03e1 in sigtimedwait () from /lib/libc.so.6
#1 0x000000000050a560 in kvm_main_loop_wait (env=0xc319e0, timeout=0)
at /home/chris/pkgs/kvm/kvm-79/qemu/qemu-kvm.c:284
#2 0x000000000050aaf7 in ap_main_loop (_env=<value optimized out>)
at /home/chris/pkgs/kvm/kvm-79/qemu/qemu-kvm.c:425
#3 0x00007f36f11ba3ea in start_thread () from /lib/libpthread.so.0
#4 0x00007f36f0852c6d in clone () from /lib/libc.so.6
#5 0x0000000000000000 in ?? ()
Any clues to help me resolve this would be much appreciated.
----------------------------------------------------------------------
>Comment By: Chris Jones (c_jones)
Date: 2008-12-10 15:29
Message:
Actually, I was too quick to say that a Fedora 8 guest is stable. Even
there, I'm seeing hangs once I get my application fully installed
(basically, once I introduce some load).
I also did an update to kvm-80 and the problem still exists (on all the
guests I've tried). That's with kvm-80 kernel modules and the kvm-80 user,
running on linux-2.6.27.8.
Thanks,
Chris
----------------------------------------------------------------------
Comment By: Chris Jones (c_jones)
Date: 2008-12-01 14:09
Message:
Alexey,
Thanks for the response. As you advised, I tried a Fedora 8 guest, and it
does seem to be much more stable. However, I really need a Debian base
system for my application. Not necessarily Ubuntu 8.10, but I haven't had
much luck with others either. Do you have any recommendations on one that
is particularly stable?
Over the weekend I tried:
Fedora 8 : Seems very stable, but I really need a debian base.
Ubuntu 8.04LTS : Same periodic hangs I was seeing on 8.10
Debian 4.0 Etch: Seems stable on the guest, but on the host, qemu
process is running 100% busy
while the guest is idle.
Any chance you know a workaround for the issue I'm seeing on etch, or can
recommend a Debian base distribution which works well with KVM?
Thanks much,
Chris
----------------------------------------------------------------------
Comment By: Technologov (technologov)
Date: 2008-11-27 07:54
Message:
In my opinion it is not the Ubuntu host that is problematic - but the guest
on KVM.
I mean that Ubuntu 8.10 guest is unstable on KVM. I have not found out
why.
If you try some better tested guest (Fedora 7/8 or Windows XP guest it
should be lots more stable).
And if you try some other host (i.e. Fedora host and run Ubuntu 8.10 guest
it will be unstable).
In short - in my opinion - the problem is not host OS, but either KVM or
it's connection with guest OS.
-Alexey E. "Technologov", 27.11.2008.
----------------------------------------------------------------------
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