3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Bonzini <pbonzini@xxxxxxxxxx> commit e9ad4ec8379ad1ba6f68b8ca1c26b50b5ae0a327 upstream. Moving the initialization earlier is needed in 4.6 because kvm_arch_init_vm is now using mmu_lock, causing lockdep to complain: [ 284.440294] INFO: trying to register non-static key. [ 284.445259] the code is fine but needs lockdep annotation. [ 284.450736] turning off the locking correctness validator. ... [ 284.528318] [<ffffffff810aecc3>] lock_acquire+0xd3/0x240 [ 284.533733] [<ffffffffa0305aa0>] ? kvm_page_track_register_notifier+0x20/0x60 [kvm] [ 284.541467] [<ffffffff81715581>] _raw_spin_lock+0x41/0x80 [ 284.546960] [<ffffffffa0305aa0>] ? kvm_page_track_register_notifier+0x20/0x60 [kvm] [ 284.554707] [<ffffffffa0305aa0>] kvm_page_track_register_notifier+0x20/0x60 [kvm] [ 284.562281] [<ffffffffa02ece70>] kvm_mmu_init_vm+0x20/0x30 [kvm] [ 284.568381] [<ffffffffa02dbf7a>] kvm_arch_init_vm+0x1ea/0x200 [kvm] [ 284.574740] [<ffffffffa02bff3f>] kvm_dev_ioctl+0xbf/0x4d0 [kvm] However, it also helps fixing a preexisting problem, which is why this patch is also good for stable kernels: kvm_create_vm was incrementing current->mm->mm_count but not decrementing it at the out_err label (in case kvm_init_mmu_notifier failed). The new initialization order makes it possible to add the required mmdrop without adding a new error label. Reported-by: Borislav Petkov <bp@xxxxxxxxx> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- virt/kvm/kvm_main.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -454,6 +454,16 @@ static struct kvm *kvm_create_vm(unsigne if (!kvm) return ERR_PTR(-ENOMEM); + spin_lock_init(&kvm->mmu_lock); + atomic_inc(¤t->mm->mm_count); + kvm->mm = current->mm; + kvm_eventfd_init(kvm); + mutex_init(&kvm->lock); + mutex_init(&kvm->irq_lock); + mutex_init(&kvm->slots_lock); + atomic_set(&kvm->users_count, 1); + INIT_LIST_HEAD(&kvm->devices); + r = kvm_arch_init_vm(kvm, type); if (r) goto out_err_no_disable; @@ -492,16 +502,6 @@ static struct kvm *kvm_create_vm(unsigne goto out_err; } - spin_lock_init(&kvm->mmu_lock); - kvm->mm = current->mm; - atomic_inc(&kvm->mm->mm_count); - kvm_eventfd_init(kvm); - mutex_init(&kvm->lock); - mutex_init(&kvm->irq_lock); - mutex_init(&kvm->slots_lock); - atomic_set(&kvm->users_count, 1); - INIT_LIST_HEAD(&kvm->devices); - r = kvm_init_mmu_notifier(kvm); if (r) goto out_err; @@ -523,6 +523,7 @@ out_err_no_disable: kfree(kvm->buses[i]); kvfree(kvm->memslots); kvm_arch_free_vm(kvm); + mmdrop(current->mm); return ERR_PTR(r); } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html