[libvirt] [PATCH 0/5] Fix deadlock in nwfilter code

Daniel P. Berrange berrange at redhat.com
Thu Jan 23 12:37:32 UTC 2014


Since we introduced fine grained locking into the QEMU driver so
that VM start can run in parallel, we appear to have caused a
race with the nwfilter code. In particular since we no longer
hold the global QEMU driver lock for the duration of VM startup
we have a lock ordering flaw. This results in deadlock when
nwfilter operations happen in parallel with VM startup. This
also affects the LXC driver.

This patch series attempts to address the problem

  https://bugzilla.redhat.com/show_bug.cgi?id=929412

the removal of the windows thread impl isn't strictly required,
I just didn't want to waste time creating a read/write lock impl
for Windows threads.

Daniel P. Berrange (5):
  Add a read/write lock implementation
  Remove windows thread implementation in favour of pthreads
  Push nwfilter update locking up to top level
  Add a mutex to serialize updates to firewall
  Turn nwfilter conf update mutex into a read/write lock

 configure.ac                           |  15 +-
 src/Makefile.am                        |   4 -
 src/conf/nwfilter_conf.c               |  23 +-
 src/conf/nwfilter_conf.h               |   3 +-
 src/libvirt_private.syms               |   8 +-
 src/lxc/lxc_driver.c                   |   6 +
 src/nwfilter/nwfilter_driver.c         |  12 +-
 src/nwfilter/nwfilter_gentech_driver.c |  21 +-
 src/nwfilter/nwfilter_gentech_driver.h |   2 +-
 src/qemu/qemu_driver.c                 |   6 +
 src/uml/uml_driver.c                   |   4 +
 src/util/virthread.c                   | 291 +++++++++++++++++++++++-
 src/util/virthread.h                   |  51 ++++-
 src/util/virthreadpthread.c            | 278 -----------------------
 src/util/virthreadpthread.h            |  49 ----
 src/util/virthreadwin32.c              | 396 ---------------------------------
 src/util/virthreadwin32.h              |  53 -----
 17 files changed, 395 insertions(+), 827 deletions(-)
 delete mode 100644 src/util/virthreadpthread.c
 delete mode 100644 src/util/virthreadpthread.h
 delete mode 100644 src/util/virthreadwin32.c
 delete mode 100644 src/util/virthreadwin32.h

-- 
1.8.4.2




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