qemu: Fix a possible deadlock in p2p migration

The function virUnrefConnect() may call virReleaseConnect() to release
the dest connection, and the function virReleaseConnect() will call
conn->driver->close().

So the function virUnrefConnect() should be surrounded by
qemuDomainObjEnterRemoteWithDriver() and
qemuDomainObjExitRemoteWithDriver() to prevent possible deadlock between
two communicating libvirt daemons.

See commit f0c8e1cb3774d6f09e2681ca1988bf235a343007 for further details.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index cff7a4311199ae96162bc53792d990d8f7c0f6c2..012ce5d67e35dc770ed6b913e7a7508d8aa3c655 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -8790,7 +8790,9 @@ static int doPeer2PeerMigrate(virDomainPtr dom,
 cleanup:
     VIR_FREE(dom_xml);
     /* don't call virConnectClose(), because that resets any pending errors */
+    qemuDomainObjEnterRemoteWithDriver(driver, vm);
     virUnrefConnect(dconn);
+    qemuDomainObjExitRemoteWithDriver(driver, vm);
 
     return ret;
 }