If @vm has flagged as "to be removed" virDomainObjListFindByNameLocked
returns NULL (although the definition actually exists). Therefore, the
possibility exits that "virHashAddEntry" will raise the error
"Duplicate key" => virDomainObjListAddObjLocked fails =>
virDomainObjEndAPI(&vm) is called and this leads to a freeing of @def
since @def is already assigned to vm->def. But actually this leads to
a double free since the common usage pattern is that the caller of
virDomainObjListAdd(Locked) is responsible for freeing @def in case of
an error.
Let's fix this by setting vm->def to NULL in case of an error.
Backtrace:
➤ bt
#0 virFree (ptrptr=0x7575757575757575)
#1 0x000003ffb5b25b3e in virDomainResourceDefFree
#2 0x000003ffb5b37c34 in virDomainDefFree
#3 0x000003ff9123f734 in qemuDomainDefineXMLFlags
#4 0x000003ff9123f7f4 in qemuDomainDefineXML
#5 0x000003ffb5cd2c84 in virDomainDefineXML
#6 0x000000011745aa82 in remoteDispatchDomainDefineXML
...
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Semantically, there is no difference between an uninitialized worker
pool and an initialized worker pool with zero workers. Let's allow the
worker pool to be initialized for max_workers=0 as well then which
makes the API more symmetric and simplifies code. Validity of the
worker pool is delegated to virThreadPoolGetMaxWorkers instead.
This patch fixes segmentation faults in
virNetServerGetThreadPoolParameters and
virNetServerSetThreadPoolParameters for the case when no worker pool
is actually initialized (max_workers=0).
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Hypervisor drivers (e.g. QEMU) assume that they run in a separate
thread from the main event loop thread otherwise deadlocks can
occur. Therefore let's report an error if max_workers < 1 is set in
the libvirtd configuration file.
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
@srv must be unlocked for the call virNetServerProcessMsg otherwise a
deadlock can occur.
Since the pointer 'srv->workers' will never be changed after
initialization and the thread pool has it's own locking we can release
the lock of 'srv' earlier. This also fixes the deadlock.
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
On start up of libvirtd the worker pool of the QEMU driver must be
initialized before trying to reconnect to all the running QEMU
instances. Otherwise segmentation faults can occur if there are QEMU
monitor events emitted.
#0 __GI___pthread_mutex_lock
#1 0x000003fffdba9e62 in virMutexLock
#2 0x000003fffdbab2dc in virThreadPoolSendJob
#3 0x000003ffd8343b70 in qemuProcessHandleSerialChanged
#4 0x000003ffd836a776 in qemuMonitorEmitSerialChange
#5 0x000003ffd8378e52 in qemuMonitorJSONHandleSerialChange
#6 0x000003ffd8378930 in qemuMonitorJSONIOProcessEvent
#7 0x000003ffd837edee in qemuMonitorJSONIOProcessLine
#8 0x000003ffd837ef86 in qemuMonitorJSONIOProcess
#9 0x000003ffd836757a in qemuMonitorIOProcess
#10 0x000003ffd836863e in qemuMonitorIO
#11 0x000003fffdb4033a in virEventPollDispatchHandles
#12 0x000003fffdb4055e in virEventPollRunOnce
#13 0x000003fffdb3e782 in virEventRunDefaultImpl
#14 0x000003fffdc89400 in virNetDaemonRun
#15 0x000000010002a816 in main
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Marc Hartmayer