Messages in this thread | | | From | Johannes Weiner <> | Subject | Re: Circular vma locking with kvm, seems to be mmu notifiers related | Date | Wed, 13 Aug 2008 10:49:10 +0200 |
| |
Hi Avi,
Avi Kivity <avi@qumranet.com> writes:
> Max Krasnyansky wrote: >> Got this on the latest mainline git. >> There are already a couple of lockdep/kvm threads. So maybe it's known. >> >> ============================================= >> [ INFO: possible recursive locking detected ] >> 2.6.27-rc2 #36 >> --------------------------------------------- >> qemu-system-x86/3445 is trying to acquire lock: >> (&anon_vma->lock){--..}, at: [<ffffffff8029f84d>] mm_take_all_locks+0x8d/0xf0 >> >> but task is already holding lock: >> (&anon_vma->lock){--..}, at: [<ffffffff8029f84d>] mm_take_all_locks+0x8d/0xf0 >> >> > > Seems to be a false positive. mmu_take_all_locks takes (surprise!) > all anon_vma->locks belonging to an mm, and takes special care not to > deadlock while doing this. > > We need to communicate this to lockdep somehow.
I think Peter already annotated this in 454ed842d55740160334efc9ad56cfef54ed37bc .
Hannes
| |