From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754806AbbJ0WIg (ORCPT ); Tue, 27 Oct 2015 18:08:36 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34877 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932224AbbJ0Va5 (ORCPT ); Tue, 27 Oct 2015 17:30:57 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Aneesh Kumar K.V" , Michael Ellerman , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 31/86] powerpc/mm: Recompute hash value after a failed update Date: Tue, 27 Oct 2015 14:29:31 -0700 Message-Id: <1445981426-19727-32-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1445981426-19727-1-git-send-email-kamal@canonical.com> References: <1445981426-19727-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt9 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Aneesh Kumar K.V" commit 36b35d5d807b7e57aff7d08e63de8b17731ee211 upstream. If we had secondary hash flag set, we ended up modifying hash value in the updatepp code path. Hence with a failed updatepp we will be using a wrong hash value for the following hash insert. Fix this by recomputing hash before insert. Without this patch we can end up with using wrong slot number in linux pte. That can result in us missing an hash pte update or invalidate which can cause memory corruption or even machine check. Fixes: 6d492ecc6489 ("powerpc/THP: Add code to handle HPTE faults for hugepages") Signed-off-by: Aneesh Kumar K.V Reviewed-by: Paul Mackerras Signed-off-by: Michael Ellerman Signed-off-by: Kamal Mostafa --- arch/powerpc/mm/hugepage-hash64.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c index 8668651..79cd39f 100644 --- a/arch/powerpc/mm/hugepage-hash64.c +++ b/arch/powerpc/mm/hugepage-hash64.c @@ -85,7 +85,6 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, BUG_ON(index >= 4096); vpn = hpt_vpn(ea, vsid, ssize); - hash = hpt_hash(vpn, shift, ssize); hpte_slot_array = get_hpte_slot_array(pmdp); if (psize == MMU_PAGE_4K) { /* @@ -101,6 +100,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, valid = hpte_valid(hpte_slot_array, index); if (valid) { /* update the hpte bits */ + hash = hpt_hash(vpn, shift, ssize); hidx = hpte_hash_index(hpte_slot_array, index); if (hidx & _PTEIDX_SECONDARY) hash = ~hash; @@ -126,6 +126,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, if (!valid) { unsigned long hpte_group; + hash = hpt_hash(vpn, shift, ssize); /* insert new entry */ pa = pmd_pfn(__pmd(old_pmd)) << PAGE_SHIFT; new_pmd |= _PAGE_HASHPTE; -- 1.9.1