From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3434FC4CEC9 for ; Wed, 18 Sep 2019 06:22:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05EEC2196E for ; Wed, 18 Sep 2019 06:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568787760; bh=AmPdtI6h8tH+deO2N2hCo9hOkNSyZkeuv+vl8Qg+icg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ax491qRMLbdS9zDfTU80qlm4yasLutUSt/bI9H2YymmwmWkDpPMYRXMxtw8h3NPxU qArjsnOKABbWLnbYNJlILFyGsFUIPubIDqJfFoOwUs9nOTiw/MZve1q3hi1XNLlO12 ty3iWPDdLBV/B8JN5RcXFcH/vMBcHF7vrWkQk0G0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729457AbfIRGWj (ORCPT ); Wed, 18 Sep 2019 02:22:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:42590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728184AbfIRGWf (ORCPT ); Wed, 18 Sep 2019 02:22:35 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7CE9B21906; Wed, 18 Sep 2019 06:22:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568787755; bh=AmPdtI6h8tH+deO2N2hCo9hOkNSyZkeuv+vl8Qg+icg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kwvMmjOH7dVmLdGn2V2u7pBK6Srlzm+WHB0BqLte0WJIMLomnMWxtCMdDoXpCYO17 vDIZnlAuB7+XIJN6Gce++GWWZjgAvM55fyKzNYs3EgmN0K2G7D/4Zsr8mcm4q2rvQy AchMP9wTgI3xQGYh8nm+L5qNHsJNbZeVlyMK1oLU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Igor Mammedov , David Hildenbrand , Christian Borntraeger , Claudio Imbrenda , Cornelia Huck , Janosch Frank Subject: [PATCH 4.19 21/50] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset() Date: Wed, 18 Sep 2019 08:19:04 +0200 Message-Id: <20190918061225.325572504@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190918061223.116178343@linuxfoundation.org> References: <20190918061223.116178343@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Igor Mammedov commit 13a17cc0526f08d1df9507f7484176371cd263a0 upstream. If userspace doesn't set KVM_MEM_LOG_DIRTY_PAGES on memslot before calling kvm_s390_vm_start_migration(), kernel will oops with: Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000483 Fault in home space mode while using kernel ASCE. AS:0000000002a2000b R2:00000001bff8c00b R3:00000001bff88007 S:00000001bff91000 P:000000000000003d Oops: 0004 ilc:2 [#1] SMP ... Call Trace: ([<001fffff804ec552>] kvm_s390_vm_set_attr+0x347a/0x3828 [kvm]) [<001fffff804ecfc0>] kvm_arch_vm_ioctl+0x6c0/0x1998 [kvm] [<001fffff804b67e4>] kvm_vm_ioctl+0x51c/0x11a8 [kvm] [<00000000008ba572>] do_vfs_ioctl+0x1d2/0xe58 [<00000000008bb284>] ksys_ioctl+0x8c/0xb8 [<00000000008bb2e2>] sys_ioctl+0x32/0x40 [<000000000175552c>] system_call+0x2b8/0x2d8 INFO: lockdep is turned off. Last Breaking-Event-Address: [<0000000000dbaf60>] __memset+0xc/0xa0 due to ms->dirty_bitmap being NULL, which might crash the host. Make sure that ms->dirty_bitmap is set before using it or return -EINVAL otherwise. Cc: Fixes: afdad61615cc ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by: Igor Mammedov Link: https://lore.kernel.org/kvm/20190911075218.29153-1-imammedo@redhat.com/ Reviewed-by: David Hildenbrand Reviewed-by: Christian Borntraeger Reviewed-by: Claudio Imbrenda Reviewed-by: Cornelia Huck Reviewed-by: Janosch Frank Signed-off-by: Janosch Frank Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman --- arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -928,6 +928,8 @@ static int kvm_s390_vm_start_migration(s /* mark all the pages in active slots as dirty */ for (slotnr = 0; slotnr < slots->used_slots; slotnr++) { ms = slots->memslots + slotnr; + if (!ms->dirty_bitmap) + return -EINVAL; /* * The second half of the bitmap is only used on x86, * and would be wasted otherwise, so we put it to good