Hi, last email hopefully. My last patch was broken because it double locked vm. I discovered that virDomainFindBy* locks vm before returning it. The new patch does not double-lock. best, Tom 0001-Use-virDomainFindbyID-and-pass-id-instead-of-a-point.patch From f2fd4cb72c8f2e01567320a643fe2d665308119e Mon Sep 17 00:00:00 2001 From: Thomas Hunger <tehunger(a)gmail.com&gt; Date: Thu, 15 Mar 2012 00:08:00 +0000 Subject: [PATCH] Use virDomainFindbyID and pass id instead of a pointer to lxcMontitorEvent. This fixes a race condition where lxcDomainDestroyFlags would acquire the driver lock. It would then kill processes in the cgroup and trigger VIR_EVENT_HANDLE_HANGUP, which in turn triggers lxcMonitorEvent. lxcMonitorEvent tries to acquire the driver lock itself, so it would block until destroy has invalidated the data "vm" points to. By using virDomainFindbyID lxcMonitorEvent avoids using an invalid vm pointer.

--- src/lxc/lxc_driver.c | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c index 3af8084..c55e164 100644 --- a/src/lxc/lxc_driver.c +++ b/src/lxc/lxc_driver.c @@ -1523,12 +1523,17 @@ static void lxcMonitorEvent(int watch, void *data) { lxc_driver_t *driver = lxc_driver; - virDomainObjPtr vm = data; + int id = (int)data; + virDomainObjPtr vm = NULL; virDomainEventPtr event = NULL; lxcDomainObjPrivatePtr priv; lxcDriverLock(driver); - virDomainObjLock(vm); + vm = virDomainFindByID(&driver->domains, id);