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8dce8b828c
The new safe console handling introduced a possibility to deadlock the
qemu driver when a new console connection forcibly disconnects a
previous console stream that belongs to an already closed connection.
The virStreamFree function calls subsequently a the virReleaseConnect
function that tries to lock the driver while discarding the connection,
but the driver was already locked in qemuDomainOpenConsole.
Backtrace of the deadlocked thread:
0 0x00007f66e5aa7f14 in __lll_lock_wait () from /lib64/libpthread.so.0
1 0x00007f66e5aa3411 in _L_lock_500 () from /lib64/libpthread.so.0
2 0x00007f66e5aa322a in pthread_mutex_lock () from/lib64/libpthread.so.0
3 0x0000000000462bbd in qemudClose ()
4 0x00007f66e6e178eb in virReleaseConnect () from/usr/lib64/libvirt.so.0
5 0x00007f66e6e19c8c in virUnrefStream () from /usr/lib64/libvirt.so.0
6 0x00007f66e6e3d1de in virStreamFree () from /usr/lib64/libvirt.so.0
7 0x00007f66e6e09a5d in virConsoleHashEntryFree () from/usr/lib64/libvirt.so.0
8 0x00007f66e6db7282 in virHashRemoveEntry () from/usr/lib64/libvirt.so.0
9 0x00007f66e6e09c4e in virConsoleOpen () from /usr/lib64/libvirt.so.0
10 0x00000000004526e9 in qemuDomainOpenConsole ()
11 0x00007f66e6e421f1 in virDomainOpenConsole () from/usr/lib64/libvirt.so.0
12 0x00000000004361e4 in remoteDispatchDomainOpenConsoleHelper ()
13 0x00007f66e6e80375 in virNetServerProgramDispatch () from/usr/lib64/libvirt.so.0
14 0x00007f66e6e7ae11 in virNetServerHandleJob () from/usr/lib64/libvirt.so.0
15 0x00007f66e6da897d in virThreadPoolWorker () from/usr/lib64/libvirt.so.0
16 0x00007f66e6da7ff6 in virThreadHelper () from/usr/lib64/libvirt.so.0
17 0x00007f66e5aa0c5c in start_thread () from /lib64/libpthread.so.0
18 0x00007f66e57e7fcd in clone () from /lib64/libc.so.6
* src/qemu/qemu_driver.c: qemuDomainOpenConsole()
-- unlock the qemu driver right after acquiring the domain
object
(cherry picked from commit
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.. | ||
conf | ||
cpu | ||
esx | ||
hyperv | ||
interface | ||
libxl | ||
locking | ||
lxc | ||
network | ||
node_device | ||
nwfilter | ||
openvz | ||
phyp | ||
qemu | ||
remote | ||
rpc | ||
secret | ||
security | ||
storage | ||
test | ||
uml | ||
util | ||
vbox | ||
vmware | ||
vmx | ||
xen | ||
xenapi | ||
xenxs | ||
datatypes.c | ||
datatypes.h | ||
driver.c | ||
driver.h | ||
dtrace2systemtap.pl | ||
fdstream.c | ||
fdstream.h | ||
gnutls_1_0_compat.h | ||
internal.h | ||
libvirt_daemon.syms | ||
libvirt_dbus.syms | ||
libvirt_driver_modules.syms | ||
libvirt_internal.h | ||
libvirt_linux.syms | ||
libvirt_network.syms | ||
libvirt_nwfilter.syms | ||
libvirt_private.syms | ||
libvirt_public.syms | ||
libvirt_qemu.syms | ||
libvirt_sasl.syms | ||
libvirt_vmx.syms | ||
libvirt_xenxs.syms | ||
libvirt-qemu.c | ||
libvirt.c | ||
libvirt.conf | ||
Makefile.am | ||
nodeinfo.c | ||
nodeinfo.h | ||
probes.d | ||
qemu_protocol-structs | ||
README | ||
remote_protocol-structs | ||
virkeepaliveprotocol-structs | ||
virnetprotocol-structs |
libvirt library code README =========================== The directory provides the bulk of the libvirt codebase. Everything except for the libvirtd daemon and client tools. The build uses a large number of libtool convenience libraries - one for each child directory, and then links them together for the final libvirt.so, although some bits get linked directly to libvirtd daemon instead. The files directly in this directory are supporting the public API entry points & data structures. There are two core shared modules to be aware of: * util/ - a collection of shared APIs that can be used by any code. This directory is always in the include path for all things built * conf/ - APIs for parsing / manipulating all the official XML files used by the public API. This directory is only in the include path for driver implementation modules * vmx/ - VMware VMX config handling (used by esx/ and vmware/) Then there are the hypervisor implementations: * esx/ - VMware ESX and GSX support using vSphere API over SOAP * hyperv/ - Microsoft Hyper-V support using WinRM * lxc/ - Linux Native Containers * openvz/ - OpenVZ containers using cli tools * phyp/ - IBM Power Hypervisor using CLI tools over SSH * qemu/ - QEMU / KVM using qemu CLI/monitor * remote/ - Generic libvirt native RPC client * test/ - A "mock" driver for testing * uml/ - User Mode Linux * vbox/ - Virtual Box using native API * vmware/ - VMware Workstation and Player using the vmrun tool * xen/ - Xen using hypercalls, XenD SEXPR & XenStore * xenapi/ - Xen using libxenserver Finally some secondary drivers that are shared for several HVs. Currently these are used by LXC, OpenVZ, QEMU, UML and Xen drivers. The ESX, Hyper-V, Power Hypervisor, Remote, Test & VirtualBox drivers all implement the secondary drivers directly * cpu/ - CPU feature management * interface/ - Host network interface management * network/ - Virtual NAT networking * nwfilter/ - Network traffic filtering rules * node_device/ - Host device enumeration * secret/ - Secret management * security/ - Mandatory access control drivers * storage/ - Storage management drivers Since both the hypervisor and secondary drivers can be built as dlopen()able modules, it is *FORBIDDEN* to have build dependencies between these directories. Drivers are only allowed to depend on the public API, and the internal APIs in the util/ and conf/ directories