From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out1-smtp.messagingengine.com ([66.111.4.25]:56767 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1036769AbdDUIdY (ORCPT ); Fri, 21 Apr 2017 04:33:24 -0400 Subject: FAILED: patch "[PATCH] s390/mm: fix CMMA vs KSM vs others" failed to apply to 4.9-stable tree To: borntraeger@de.ibm.com, schwidefsky@de.ibm.com Cc: From: Date: Fri, 21 Apr 2017 10:33:14 +0200 Message-ID: <149276359443209@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From a8f60d1fadf7b8b54449fcc9d6b15248917478ba Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Sun, 9 Apr 2017 22:09:38 +0200 Subject: [PATCH] s390/mm: fix CMMA vs KSM vs others On heavy paging with KSM I see guest data corruption. Turns out that KSM will add pages to its tree, where the mapping return true for pte_unused (or might become as such later). KSM will unmap such pages and reinstantiate with different attributes (e.g. write protected or special, e.g. in replace_page or write_protect_page)). This uncovered a bug in our pagetable handling: We must remove the unused flag as soon as an entry becomes present again. Cc: stable@vger.kernel.org Signed-of-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 93e37b12e882..ecec682bb516 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1051,6 +1051,8 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, { if (!MACHINE_HAS_NX) pte_val(entry) &= ~_PAGE_NOEXEC; + if (pte_present(entry)) + pte_val(entry) &= ~_PAGE_UNUSED; if (mm_has_pgste(mm)) ptep_set_pte_at(mm, addr, ptep, entry); else