Am Donnerstag 10 März 2011 07:45:49 schrieb Jim Fehlig:
Add a new xen driver based on libxenlight [1], which is the primary toolstack starting with Xen 4.1.0. The driver is stateful, runs privileged only, and is accessed with libxl:/// URI.
V5: - Ensure events are unregistered when domain private data is destroyed. Discovered and fixed by Markus Gross.
V4: - Handle restart of libvirtd, reconnecting to previously started domains - Rebased to current master - Tested against Xen 4.1 RC7-pre (c/s 22961:c5d121fd35c0)
V3: - Reserve vnc port within driver when autoport=yes
V2: - Update to Xen 4.1 RC6-pre (c/s 22940:5a4710640f81) - Rebased to current master - Plug memory leaks found by Stefano Stabellini and valgrind - Handle SHUTDOWN_crash domain death event
[1] http://lists.xensource.com/archives/html/xen-devel/2009-11/msg00436.html
The libxlEventHandler needs to hold an extra reference to the corresponding "vm" object. Otherwise the handler will try to access an invalid vm object under certain race conditions. I fixed it using the following patch. Now the libxl driver keeps an extra reference of the vm object for the event handler and specifies a free callback function. This free callback function removes the reference to the vm object to avoid a memory leak. diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 7559949..30f3700 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -235,6 +235,14 @@ cleanup: libxl_free_event(&event); } +static void +libxlDomainUnwatch(void *data) +{ + virDomainObjPtr vm = data; + /* Remove reference from handler */ + virDomainObjUnref(vm); +} + /* * Register domain events with libxenlight and insert event handles * in libvirt's event loop. @@ -257,17 +265,20 @@ libxlCreateDomEvents(virDomainObjPtr vm) if (fd < 0) goto error; + /* Hold an extra reference for the event handler */ + virDomainObjRef(vm); priv->waiterFD = fd; if ((priv->eventHdl = virEventAddHandle( fd, VIR_EVENT_HANDLE_READABLE | VIR_EVENT_HANDLE_ERROR, libxlEventHandler, - vm, NULL)) < 0) + vm, libxlDomainUnwatch)) < 0) goto error; return 0; error: + virDomainObjUnref(vm); libxl_free_waiter(priv->dWaiter); VIR_FREE(priv->dWaiter); priv->eventHdl = -1;