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@xxxxxxxxxx> > >>> > >>> 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@xxxxxxxxxx> > >>> --- > >>> 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 ? 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 :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list