Fixes a possible 'use after free' of kvm variable. It does use mutex_unlock(&kvm->lock) after possible freeing a variable with kvm_put_kvm(kvm).
Signed-off-by: Leonardo Bras <leona...@linux.ibm.com> --- arch/powerpc/kvm/book3s_64_vio.c | 3 +-- virt/kvm/kvm_main.c | 8 ++++---- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 5834db0a54c6..a402ead833b6 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -316,14 +316,13 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, if (ret >= 0) list_add_rcu(&stt->list, &kvm->arch.spapr_tce_tables); - else - kvm_put_kvm(kvm); mutex_unlock(&kvm->lock); if (ret >= 0) return ret; + kvm_put_kvm(kvm); kfree(stt); fail_acct: account_locked_vm(current->mm, kvmppc_stt_pages(npages), false); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 13efc291b1c7..f37089b60d09 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2744,10 +2744,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) /* Now it's all set up, let userspace reach it */ kvm_get_kvm(kvm); r = create_vcpu_fd(vcpu); - if (r < 0) { - kvm_put_kvm(kvm); + if (r < 0) goto unlock_vcpu_destroy; - } kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu; @@ -2771,6 +2769,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) mutex_lock(&kvm->lock); kvm->created_vcpus--; mutex_unlock(&kvm->lock); + if (r < 0) + kvm_put_kvm(kvm); return r; } @@ -3183,10 +3183,10 @@ static int kvm_ioctl_create_device(struct kvm *kvm, kvm_get_kvm(kvm); ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC); if (ret < 0) { - kvm_put_kvm(kvm); mutex_lock(&kvm->lock); list_del(&dev->vm_node); mutex_unlock(&kvm->lock); + kvm_put_kvm(kvm); ops->destroy(dev); return ret; } -- 2.23.0