On Thu, Oct 31, 2013 at 10:23:25AM -0400, Cole Robinson wrote:
On 10/29/2013 11:22 AM, Cole Robinson wrote:
On 10/29/2013 10:25 AM, Daniel P. Berrange wrote:
On Mon, Oct 28, 2013 at 01:22:39PM -0400, Cole Robinson wrote:
On 10/28/2013 01:14 PM, Daniel P. Berrange wrote:
On Mon, Oct 28, 2013 at 01:08:45PM -0400, Cole Robinson wrote:
On 10/28/2013 01:06 PM, Daniel P. Berrange wrote: > On Mon, Oct 28, 2013 at 01:03:49PM -0400, Cole Robinson wrote: >> On 10/28/2013 07:52 AM, Daniel P. Berrange wrote: >>> From: "Daniel P. Berrange" <berrange@redhat.com> >>> >>> The following sequence >>> >>> 1. Define a persistent QMEU guest >>> 2. Start the QEMU guest >>> 3. Stop libvirtd >>> 4. Kill the QEMU process >>> 5. Start libvirtd >>> 6. List persistent guets >>> >>> At the last step, the previously running persistent guest >>> will be missing. This is because of a race condition in the >>> QEMU driver startup code. It does >>> >>> 1. Load all VM state files >>> 2. Spawn thread to reconnect to each VM >>> 3. Load all VM config files >>> >>> Only at the end of step 3, does the 'virDomainObjPtr' get >>> marked as "persistent". There is therefore a window where >>> the thread reconnecting to the VM will remove the persistent >>> VM from the list. >>> >>> The easy fix is to simply switch the order of steps 2 & 3. >>> >>> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> >>> --- >>> src/qemu/qemu_driver.c | 3 +-- >>> 1 file changed, 1 insertion(+), 2 deletions(-) >>> >>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c >>> index c613967..9c3daad 100644 >>> --- a/src/qemu/qemu_driver.c >>> +++ b/src/qemu/qemu_driver.c >>> @@ -816,8 +816,6 @@ qemuStateInitialize(bool privileged, >>> >>> conn = virConnectOpen(cfg->uri); >>> >>> - qemuProcessReconnectAll(conn, qemu_driver); >>> - >>> /* Then inactive persistent configs */ >>> if (virDomainObjListLoadAllConfigs(qemu_driver->domains, >>> cfg->configDir, >>> @@ -828,6 +826,7 @@ qemuStateInitialize(bool privileged, >>> NULL, NULL) < 0) >>> goto error; >>> >>> + qemuProcessReconnectAll(conn, qemu_driver); >>> >>> virDomainObjListForEach(qemu_driver->domains, >>> qemuDomainSnapshotLoad, >>> >> >> I tried testing this patch to see if it would fix: >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1015246 >> >> from current master I did: >> >> git revert a924d9d083c215df6044387057c501d9aa338b96 >> reproduce the bug >> git am <your-patch> >> >> But the daemon won't even start up after your patch is built: >> >> (gdb) bt >> #0 qemuMonitorOpen (vm=vm@entry=0x7fffd4211090, config=0x0, json=false, >> cb=cb@entry=0x7fffddcae720 <monitorCallbacks>, >> opaque=opaque@entry=0x7fffd419b840) at qemu/qemu_monitor.c:852
Sorry for not being clear: The daemon crashes, that's the backtrace.
Hmm config is NULL - does the state XML files not include the monitor info perhaps ?
I see:
pidfile for busted VM in /var/run/libvirt/qemu nothing in /var/cache/libvirt/qemu no state that I can see in /var/lib/libvirt/qemu
But I'm not sure where it's supposed to be stored.
FWIW reproducing this state was pretty simple: revert a924d9d083c215df6044387057c501d9aa338b96, edit an existing x86 guest to remove all <video> and <graphics> devices, start the guest, libvirtd crashes.
Ok, I believe you probably have SELinux disabled on your machine or in libvirtd. With SELinux enabled you hit another bug first
2013-10-29 13:50:11.711+0000: 17579: error : qemuConnectMonitor:1401 : Failed to set security context for monitor for rhel6x86_64
which prevents hitting the crash you report. The fix is the same in both cases - we must skip VMs with PID of zero. I've sent a v2 patch.
Hmm, selinux is permissive here but not disabled. But I'll try your patches and report back.
Applied both patches, the original bug report and the crash I reported here are both fixed. Thanks Dan!
Cool, thanks for confirming. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|