Re: [libvirt] [PATCH] nwfilter: fix deadlock caused updating network device and nwfilter

On Wed, Nov 05, 2014 at 03:02:03PM +0100, Pavel Hrdina wrote: > Commit 6e5c79a1 tried to fix deadlock between nwfilter{Define,Undefine} > and starting of guest, but this same deadlock is also for > updating/attaching network device to domain. > > The deadlock was introduced by removing global QEMU driver lock because > nwfilter was counting on this lock and ensure that all driver locks are > locked inside of nwfilter{Define,Undefine}. > > This patch extends usage of virNWFilterReadLockFilterUpdates to prevent > the deadlock for all possible paths in QEMU driver. LXC and UML drivers > still have global lock. ACK, conceptually it makes sense that we need to hold the read lock in these methods. Concurrency should still be good because it is only a read lock, not a write lock. Regards, Daniel