From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753517AbdLLN6r (ORCPT ); Tue, 12 Dec 2017 08:58:47 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:59818 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752622AbdLLMsk (ORCPT ); Tue, 12 Dec 2017 07:48:40 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Cermak , Hendrik Brueckner , Heiko Carstens , Martin Schwidefsky Subject: [PATCH 4.14 059/164] s390/mm: fix off-by-one bug in 5-level page table handling Date: Tue, 12 Dec 2017 13:43:59 +0100 Message-Id: <20171212123446.618376442@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171212123443.785979602@linuxfoundation.org> References: <20171212123443.785979602@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Heiko Carstens commit 8d306f53b63099fec2d56300149e400d181ba4f5 upstream. Martin Cermak reported that setting a uprobe doesn't work. Reason for this is that the common uprobes code tries to get an unmapped area at the last possible page within an address space. This broke with commit 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") which introduced an off-by-one bug which prevents to map anything at the last possible page within an address space. The check with the off-by-one bug however can be removed since with commit 8ab867cb0806 ("s390/mm: fix BUG_ON in crst_table_upgrade") the necessary check is done at both call sites. Reported-by: Martin Cermak Bisected-by: Thomas Richter Fixes: 1aea9b3f9210 ("s390/mm: implement 5 level pages tables") Reviewed-by: Hendrik Brueckner Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/mm/pgalloc.c | 2 -- 1 file changed, 2 deletions(-) --- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -85,8 +85,6 @@ int crst_table_upgrade(struct mm_struct /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ VM_BUG_ON(mm->context.asce_limit < _REGION2_SIZE); - if (end >= TASK_SIZE_MAX) - return -ENOMEM; rc = 0; notify = 0; while (mm->context.asce_limit < end) {