From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934030AbbIVSTr (ORCPT ); Tue, 22 Sep 2015 14:19:47 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42751 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759330AbbIVRxp (ORCPT ); Tue, 22 Sep 2015 13:53:45 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Juergen Gross , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , bp@suse.de, Ingo Molnar , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 003/102] x86/ldt: Correct LDT access in single stepping logic Date: Tue, 22 Sep 2015 10:50:59 -0700 Message-Id: <1442944358-1248-4-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1442944358-1248-1-git-send-email-kamal@canonical.com> References: <1442944358-1248-1-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-ckt7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Juergen Gross commit 136d9d83c07c5e30ac49fc83b27e8c4842f108fc upstream. Commit 37868fe113ff ("x86/ldt: Make modify_ldt synchronous") introduced a new struct ldt_struct anchored at mm->context.ldt. convert_ip_to_linear() was changed to reflect this, but indexing into the ldt has to be changed as the pointer is no longer void *. Signed-off-by: Juergen Gross Reviewed-by: Andy Lutomirski Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bp@suse.de Link: http://lkml.kernel.org/r/1438848278-12906-1-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar Signed-off-by: Kamal Mostafa --- arch/x86/kernel/step.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 6273324..0ccb53a 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -28,11 +28,11 @@ unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *re struct desc_struct *desc; unsigned long base; - seg &= ~7UL; + seg >>= 3; mutex_lock(&child->mm->context.lock); if (unlikely(!child->mm->context.ldt || - (seg >> 3) >= child->mm->context.ldt->size)) + seg >= child->mm->context.ldt->size)) addr = -1L; /* bogus selector, access would fault */ else { desc = &child->mm->context.ldt->entries[seg]; -- 1.9.1