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Michal Privoznik
f417ad07df
https://bugzilla.redhat.com/show_bug.cgi?id=1018267 The aim of virObject refing and urefing is to tell where the object is to be used and when is no longer needed. Hence any object shouldn't be used after it has been unrefed, as we might be the last to hold the reference. The better way is to call virObjectUnref() *after* the last object usage. In this specific case, the monitor EOF handler was called after the qemuMonitorIO called virObjectUnref. Not only that @mon was disposed (which is not used in the handler anyway) but the @mon->vm which is causing a SIGSEGV: 2013-11-15 10:17:54.425+0000: 20110: error : qemuMonitorIO:688 : internal error: early end of file from monitor: possible problem: qemu-kvm: -incoming tcp:01.01.01.0:49152: Failed to bind socket: Cannot assign requested address Program received signal SIGSEGV, Segmentation fault. qemuProcessHandleMonitorEOF (mon=<optimized out>, vm=0x7fb728004170) at qemu/qemu_process.c:299 299 if (priv->beingDestroyed) { (gdb) p *priv Cannot access memory at address 0x0 (gdb) p vm $1 = (virDomainObj *) 0x7fb728004170 (gdb) p *vm $2 = {parent = {parent = {magic = 3735928559, refs = 0, klass = 0xdeadbeef}, lock = {lock = {__data = {__lock = 2, __count = 0, __owner = 20110, __nusers = 1, __kind = 0, __spins = 0, __list = {__prev = 0x0, __next = 0x0}}, __size = "\002\000\000\000\000\000\000\000\216N\000\000\001", '\000' <repeats 26 times>, __align = 2}}}, pid = 0, state = {state = 0, reason = 0}, autostart = 0, persistent = 0, updated = 0, def = 0x0, newDef = 0x0, snapshots = 0x0, current_snapshot = 0x0, hasManagedSave = false, privateData = 0x0, privateDataFreeFunc = 0x0, taint = 304} Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>