Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754938AbaFWNLU (ORCPT ); Mon, 23 Jun 2014 09:11:20 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:37189 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754813AbaFWNFN (ORCPT ); Mon, 23 Jun 2014 09:05:13 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Oleg Nesterov , Paolo Bonzini , Luis Henriques Subject: [PATCH 3.11 78/93] KVM: async_pf: mm->mm_users can not pin apf->mm Date: Mon, 23 Jun 2014 14:02:57 +0100 Message-Id: <1403528592-2163-79-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1403528592-2163-1-git-send-email-luis.henriques@canonical.com> References: <1403528592-2163-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.12 -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: Luis Henriques --- virt/kvm/async_pf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index b197950ac4d5..595226d5ccb5 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -87,7 +87,7 @@ static void async_pf_execute(struct work_struct *work) if (waitqueue_active(&vcpu->wq)) wake_up_interruptible(&vcpu->wq); - mmdrop(mm); + mmput(mm); kvm_put_kvm(vcpu->kvm); } @@ -100,7 +100,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) 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); } @@ -169,7 +169,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, 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 @@ -187,7 +187,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, 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; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/