Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
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Peter Krempa 3d3de46a67 qemu: Fix deadlock when qemuDomainOpenConsole cleans up a connection
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
2012-04-11 10:45:53 +02:00
.gnulib@d5612c714c build: prohibit cross-inclusion 2012-03-02 06:22:43 -07:00
daemon Switch libvirtd config loading code to use error APIs 2012-04-10 11:12:27 +01:00
docs Fix parallel build in docs/ directory 2012-04-04 14:33:27 +01:00
examples Revert "Refactor the libvirt RPM daemon pieces" 2012-04-03 14:49:31 +08:00
gnulib build: fix mingw ssize_t, syntax check 2012-03-30 11:10:54 -06:00
include snapshot: add atomic create flag 2012-03-23 16:38:20 -06:00
m4 Enable all warnings permanently & default to -Werror for GIT builds 2012-03-27 17:08:06 +01:00
po daemon: Add libvirtd-config.c to the list of files to translate 2012-04-10 09:51:51 -06:00
python Fix compilation error on 32bit 2012-04-10 06:24:03 -04:00
src qemu: Fix deadlock when qemuDomainOpenConsole cleans up a connection 2012-04-11 10:45:53 +02:00
tests tests: Fix libvirtdconftest in VPATH build 2012-04-11 09:57:21 +02:00
tools virsh: Clean up usage of boolean flag variables 2012-04-10 15:50:23 +02:00
.dir-locals.el maint: let emacs avoid tabs in rng files 2011-08-13 08:56:26 -06:00
.gitignore Replace daemon-conf test script with a proper test case 2012-04-10 11:13:44 +01:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap maint: prune duplicate listings in AUTHORS 2012-02-03 09:56:45 -07:00
AUTHORS UML: fix iteration over consoles 2012-04-09 10:21:07 -06:00
autobuild.sh Enable all warnings permanently & default to -Werror for GIT builds 2012-03-27 17:08:06 +01:00
autogen.sh build: allow for local gnulib diffs 2011-11-09 09:03:33 -07:00
bootstrap build: update to latest gnulib 2012-02-29 10:27:40 -07:00
bootstrap.conf Pull in GNULIB regex module for benefit of test suite on Win32 2012-04-04 14:33:27 +01:00
cfg.mk build: fix mingw ssize_t, syntax check 2012-03-30 11:10:54 -06:00
ChangeLog-old virterror.c: Fix several spelling mistakes 2012-02-03 11:32:51 -07:00
configure.ac Don't install sysctl file on non-Linux hosts 2012-04-04 19:31:40 +01:00
COPYING.LIB remove all trailing blank lines 2009-07-16 15:06:42 +02:00
HACKING Document STREQ_NULLABLE and STRNEQ_NULLABLE 2011-10-06 16:50:38 +02:00
libvirt.pc.in Fix typos in API XML file paths 2012-02-15 11:29:38 +00:00
libvirt.spec.in Fix initial hypervisor conditionals 2012-04-04 10:54:20 +01:00
Makefile.am maint: add missing copyright notices 2011-07-28 15:01:17 -06:00
Makefile.nonreentrant Ban use of all inet_* functions 2010-10-22 11:59:23 +01:00
mingw32-libvirt.spec.in Fix typos in API XML file paths 2012-02-15 11:29:38 +00:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking maint: relax git minimum version 2010-02-24 14:29:27 -05:00
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00

         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>