From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758252AbaEKUAF (ORCPT ); Sun, 11 May 2014 16:00:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47963 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757351AbaEKTUy (ORCPT ); Sun, 11 May 2014 15:20:54 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oleg Nesterov , Paolo Bonzini Subject: [PATCH 3.14 09/83] KVM: async_pf: mm->mm_users can not pin apf->mm Date: Sun, 11 May 2014 21:19:10 +0200 Message-Id: <20140511191908.320176620@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140511191907.024339448@linuxfoundation.org> References: <20140511191907.024339448@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov commit 41c22f626254b9dc0376928cae009e73d1b6a49a upstream. get_user_pages(mm) is simply wrong if mm->mm_users == 0 and exit_mmap/etc was already called (or is in progress), mm->mm_count can only pin mm->pgd and mm_struct itself. Change kvm_setup_async_pf/async_pf_execute to inc/dec mm->mm_users. kvm_create_vm/kvm_destroy_vm play with ->mm_count too but this case looks fine at first glance, it seems that this ->mm is only used to verify that current->mm == kvm->mm. Signed-off-by: Oleg Nesterov Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- virt/kvm/async_pf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -85,7 +85,7 @@ static void async_pf_execute(struct work if (waitqueue_active(&vcpu->wq)) wake_up_interruptible(&vcpu->wq); - mmdrop(mm); + mmput(mm); kvm_put_kvm(vcpu->kvm); } @@ -98,7 +98,7 @@ void kvm_clear_async_pf_completion_queue typeof(*work), queue); list_del(&work->queue); if (cancel_work_sync(&work->work)) { - mmdrop(work->mm); + mmput(work->mm); kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ kmem_cache_free(async_pf_cache, work); } @@ -162,7 +162,7 @@ int kvm_setup_async_pf(struct kvm_vcpu * work->addr = gfn_to_hva(vcpu->kvm, gfn); work->arch = *arch; work->mm = current->mm; - atomic_inc(&work->mm->mm_count); + atomic_inc(&work->mm->mm_users); kvm_get_kvm(work->vcpu->kvm); /* this can't really happen otherwise gfn_to_pfn_async @@ -180,7 +180,7 @@ int kvm_setup_async_pf(struct kvm_vcpu * return 1; retry_sync: kvm_put_kvm(work->vcpu->kvm); - mmdrop(work->mm); + mmput(work->mm); kmem_cache_free(async_pf_cache, work); return 0; }