Re: [libvirt] [PATCH 4/4] qemu: Obtain reference on monConfig

Because we allow a QEMU_JOB_DESTROY to occur while we're starting up and we drop the @vm lock prior to qemuMonitorOpen, it's possible that a domain destroy operation "wins" the race, calls qemuProcessStop which will free and reinitialize priv->monConfig. Depending on the exact timing either qemuMonitorOpen will be passed a NULL @config variable or it will be using free'd (and possibly reclaimed) memory as the @config parameter - neither of which is good. Resolve this by localizing the @monConfig, taking an extra reference, and then once we get the @vm lock again removing our reference since we are done with it. Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- src/qemu/qemu_process.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index a8dab92dd6..988c6b1537 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -1776,6 +1776,7 @@ qemuConnectMonitor(virQEMUDriverPtr driver, virDomainObjPtr vm, int asyncJob, qemuDomainObjPrivatePtr priv = vm->privateData; qemuMonitorPtr mon = NULL; unsigned long long timeout = 0; + virDomainChrSourceDefPtr monConfig; if (qemuSecuritySetDaemonSocketLabel(driver->securityManager, vm->def) < 0) { VIR_ERROR(_("Failed to set security context for monitor for %s"), @@ -1794,10 +1795,12 @@ qemuConnectMonitor(virQEMUDriverPtr driver, virDomainObjPtr vm, int asyncJob, virObjectRef(vm); ignore_value(virTimeMillisNow(&priv->monStart)); + monConfig = priv->monConfig; + virObjectRef(monConfig); virObjectUnlock(vm); mon = qemuMonitorOpen(vm, - priv->monConfig, + monConfig, priv->monJSON, timeout, &monitorCallbacks, @@ -1813,6 +1816,7 @@ qemuConnectMonitor(virQEMUDriverPtr driver, virDomainObjPtr vm, int asyncJob, virObjectLock(vm); virObjectUnref(vm); + virObjectUnref(monConfig);

priv->monStart = 0; if (!virDomainObjIsActive(vm)) { -- 2.13.6 -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list