Daniel P. Berrange ac903dbdc7 Add a mutex to serialize updates to firewall ... The nwfilter conf update mutex previously serialized updates to the internal data structures for firewall rules, and updates to the firewall itself. The latter was recently turned into a read/write lock, and filter instantiation allowed to proceed in parallel. It was believed that this was ok, since each filter is created on a separate iptables/ebtables chain. It turns out that there is a subtle lock ordering problem on virNWFilterObjPtr instances. __virNWFilterInstantiateFilter will hold a lock on the virNWFilterObjPtr it is instantiating. This in turn invokes virNWFilterInstantiate which then invokes virNWFilterDetermineMissingVarsRec which then invokes virNWFilterObjFindByName. This iterates over every single virNWFilterObjPtr in the list, locking them and checking their name. So if 2 or more threads try to instantiate a filter in parallel, they'll all hold 1 lock at the top level in the __virNWFilterInstantiateFilter method which will cause the other thread to deadlock in virNWFilterObjFindByName. The fix is to add an exclusive mutex to serialize the execution of __virNWFilterInstantiateFilter. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> (cherry picked from commit 925de19ed7)		2014-03-10 12:25:24 +00:00
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nwfilter_dhcpsnoop.c	Don't pass virConnectPtr in nwfilter 'struct domUpdateCBStruct'	2014-02-06 12:46:58 +02:00
nwfilter_dhcpsnoop.h	maint: fix up copyright notice inconsistencies	2012-09-20 16:30:55 -06:00
nwfilter_driver.c	Add a mutex to serialize updates to firewall	2014-03-10 12:25:24 +00:00
nwfilter_driver.h	maint: fix up copyright notice inconsistencies	2012-09-20 16:30:55 -06:00
nwfilter_ebiptables_driver.c	nwfilter: Use -m conntrack rather than -m state	2013-08-06 20:30:46 -04:00
nwfilter_ebiptables_driver.h	maint: fix up copyright notice inconsistencies	2012-09-20 16:30:55 -06:00
nwfilter_gentech_driver.c	Add a mutex to serialize updates to firewall	2014-03-10 12:25:24 +00:00
nwfilter_gentech_driver.h	Add a mutex to serialize updates to firewall	2014-03-10 12:25:24 +00:00
nwfilter_learnipaddr.c	Don't pass virConnectPtr in nwfilter 'struct domUpdateCBStruct'	2014-02-06 12:46:58 +02:00
nwfilter_learnipaddr.h	maint: fix up copyright notice inconsistencies	2012-09-20 16:30:55 -06:00