From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-348652-1524840374-2-5269904048248465466 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES enda, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1524840371; b=aYRFbOunYMvcmGqnTtuS08isSesTjLhpsVU5tEB40gj8H6i0G1 S89/4wAJ1Z5AH8zYEhE8NvpoLoKDVg/kHPQ/mCzeV7r7XLxJIo7YtBHnsiFqf8wA f/5vot6k+qmj9rL5X9tgMUcWdDikGzt1WUEIJJVqe7lNJAlakoLeUNtA01K1H6yw HJ6J1uzCwMDd1SKL6IvLkEIUhF5d5vRwslKukXExkSEOnvMzOqt8lrn4Al2ELuHB B0FSGwfoz/2Tsg2rzEJPkbyWdshgpgd/89KFNn1ZCeELbNfWn0X0aYiRjAiL9W3N Y3J0769Q+2mZaKcJzU0xhC6XD4bwQ/qdPO4A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1524840371; bh=sqdPkHjq1KGTd79Uo1nTDYG4fB6tq5 qPqfF/7PiNAeI=; b=TiH9QqPvm3E2d+Q6b2QVOH+SXrjsZpnPkXxDKhTPXtv9W6 K5w4nEXVsgoMkV1YGFEHwF1aKcZ9E43vUf65jocPDmRWAuv5lcYrCS9tiFBW26an rpNxyXIv+owv66KkwgKOU9880KxmoNNCuvgEP6+9QU1BQTc41lQcVWxvJeKGui5A 6o5WLNBhRtEbl3qCr4nF1JvW0fORqPtvPGugQdZrvqY6fDAKz12Y2t9W+1ck1gG0 i/XEkzFFsVIhq7KEGhMyOi1mFbr17kerCH7//2+UkUHpkYejpn4aG9+QLbu8BOnU unBFWMUDtcdYXdm61WPYaatfrUKiPpV98IgzgE6Q== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfCER4Aht/w5RGtMnr/k980LepKmaUPjWMkzzeinXKCBSqp0bPs/qW97e9pd7GDoWvk+wcdq9K7iuTQ33VfnNeV9TGc0GrUsyPEc5AHqkaky+FyXLG2Gh hDfAVrkfjLgnCSzu22pD8ApR4n2OcYOEL6hoLQ2U2DjdhOLS8VYKamDSajRSSzCdzbTPBQCs+d7sLekuJbuRyVvJHOAx8CV9GM6TTLc4FQTuhMfG6bixJU/P X-CM-Analysis: v=2.3 cv=NPP7BXyg c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=Kd1tUaAdevIA:10 a=VnNF1IyMAAAA:8 a=ag1SF4gXAAAA:8 a=FF4WHPk0oZmug9hKHIwA:9 a=QEXdDO2ut3YA:10 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934426AbeD0OIJ (ORCPT ); Fri, 27 Apr 2018 10:08:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:53740 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934424AbeD0OIE (ORCPT ); Fri, 27 Apr 2018 10:08:04 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBD5D21864 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Schwidefsky , Farhan Ali , Christian Borntraeger Subject: [PATCH 4.14 54/80] s390/entry.S: fix spurious zeroing of r0 Date: Fri, 27 Apr 2018 15:58:47 +0200 Message-Id: <20180427135735.675188624@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180427135732.928644313@linuxfoundation.org> References: <20180427135732.928644313@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky From: Christian Borntraeger [ Upstream commit d3f468963cd6fd6d2aa5e26aed8b24232096d0e1 ] when a system call is interrupted we might call the critical section cleanup handler that re-does some of the operations. When we are between .Lsysc_vtime and .Lsysc_do_svc we might also redo the saving of the problem state registers r0-r7: .Lcleanup_system_call: [...] 0: # update accounting time stamp mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER # set up saved register r11 lg %r15,__LC_KERNEL_STACK la %r9,STACK_FRAME_OVERHEAD(%r15) stg %r9,24(%r11) # r11 pt_regs pointer # fill pt_regs mvc __PT_R8(64,%r9),__LC_SAVE_AREA_SYNC ---> stmg %r0,%r7,__PT_R0(%r9) The problem is now, that we might have already zeroed out r0. The fix is to move the zeroing of r0 after sysc_do_svc. Reported-by: Farhan Ali Fixes: 7041d28115e91 ("s390: scrub registers on kernel entry and KVM exit") Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky Signed-off-by: Martin Schwidefsky Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/entry.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -426,13 +426,13 @@ ENTRY(system_call) UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP stmg %r0,%r7,__PT_R0(%r11) - # clear user controlled register to prevent speculative use - xgr %r0,%r0 mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC mvc __PT_PSW(16,%r11),__LC_SVC_OLD_PSW mvc __PT_INT_CODE(4,%r11),__LC_SVC_ILC stg %r14,__PT_FLAGS(%r11) .Lsysc_do_svc: + # clear user controlled register to prevent speculative use + xgr %r0,%r0 # load address of system call table lg %r10,__THREAD_sysc_table(%r13,%r12) llgh %r8,__PT_INT_CODE+2(%r11)