On Tue, Jul 18, 2017 at 09:03:47AM -0300, Marcelo Tosatti wrote: > > wait_lock for mmu_lock, being allocated in kmalloc memory, > can't be tracked by LOCKDEP. > > Disable LOCKDEP verification for it. > > Fixes > > INFO: trying to register non-static key. > the code is fine but needs lockdep annotation. > turning off the locking correctness validator. > CPU: 0 PID: 12386 Comm: qemu-kvm Not tainted 3.10.0-631.rt56.546.el7.x86_64.debug #1 > Hardware name: To be filled by O.E.M. To be filled by O.E.M./PMH61ML, BIOS 4.6.4 07/14/2011 > 0000000000000002 00000000ee340fa8 ffff88008e2d7bc0 ffffffffa57534fc > ffff88008e2d7bd0 ffffffffa574ce9f ffff88008e2d7c50 ffffffffa510e565 > ffff88008e2d7bf8 00000001a50cf83d 0000000000000000 ffff880000000000 > Call Trace: > [<ffffffffa57534fc>] dump_stack+0x19/0x1b > [<ffffffffa574ce9f>] register_lock_class.part.27+0x38/0x3c > [<ffffffffa510e565>] __lock_acquire+0xcc5/0xdc0 > [<ffffffffa510efb2>] lock_acquire+0xb2/0x230 > [<ffffffffa5759ccd>] ? rt_spin_lock_slowlock+0x6d/0x3c0 > [<ffffffffa575c5f0>] _raw_spin_lock_irqsave+0x70/0xc0 > [<ffffffffa5759ccd>] ? rt_spin_lock_slowlock+0x6d/0x3c0 > [<ffffffffa5759ccd>] rt_spin_lock_slowlock+0x6d/0x3c0 > [<ffffffffa575b7ac>] rt_spin_lock+0x2c/0x60 > [<ffffffffc09b387f>] kvm_page_track_register_notifier+0x1f/0x60 [kvm] > [<ffffffffc099a8eb>] kvm_mmu_init_vm+0x2b/0x30 [kvm] > [<ffffffffc0987e04>] kvm_arch_init_vm+0x264/0x290 [kvm] > [<ffffffffc096a14e>] kvm_dev_ioctl+0xde/0x740 [kvm] > [<ffffffffa5250d45>] do_vfs_ioctl+0x365/0x5b0 > [<ffffffffa5251031>] SyS_ioctl+0xa1/0xc0 > [<ffffffffa57656ed>] tracesys+0xdd/0xe2 > --------------------------- > | preempt count: 00000001 ] > | 1-level deep critical section nesting: > ---------------------------------------- > .. [<ffffffffa575c5cd>] .... _raw_spin_lock_irqsave+0x4d/0xc0 > .....[<ffffffffa5759ccd>] .. ( <= rt_spin_lock_slowlock+0x6d/0x3c0) > > > Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 7e80f62..6375db8 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -613,6 +613,8 @@ static struct kvm *kvm_create_vm(unsigned long type) > return ERR_PTR(-ENOMEM); > > spin_lock_init(&kvm->mmu_lock); > + > + lockdep_set_novalidate_class(&kvm->mmu_lock.lock.wait_lock); > mmgrab(current->mm); > kvm->mm = current->mm; > kvm_eventfd_init(kvm); This doesn't make sense... It looks like a spin_lock_init() is missing, at which point it'll try and use the lock address itself and then bails because that is in dynamic memory. That doesn't mean you cannot initialize it properly. And using novalidate for this is absolutely bonkers.
