From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E326C433C1 for ; Wed, 31 Mar 2021 08:45:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F42160238 for ; Wed, 31 Mar 2021 08:45:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232113AbhCaIpL (ORCPT ); Wed, 31 Mar 2021 04:45:11 -0400 Received: from smtp.gentoo.org ([140.211.166.183]:57624 "EHLO smtp.gentoo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230080AbhCaIpH (ORCPT ); Wed, 31 Mar 2021 04:45:07 -0400 Received: by sf.home (Postfix, from userid 1000) id E54155A22061; Wed, 31 Mar 2021 09:44:56 +0100 (BST) From: Sergei Trofimovich To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Sergei Trofimovich , Oleg Nesterov , linux-ia64@vger.kernel.org, "Dmitry V . Levin" Subject: [PATCH] ia64: fix user_stack_pointer() for ptrace() Date: Wed, 31 Mar 2021 09:44:47 +0100 Message-Id: <20210331084447.2561532-1-slyfox@gentoo.org> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ia64 has two stacks: - memory stack (or stack), pointed at by by r12 - register backing store (register stack), pointed at ar.bsp/ar.bspstore with complications around dirty register frame on CPU. In https://bugs.gentoo.org/769614 Dmitry noticed that PTRACE_GET_SYSCALL_INFO returns register stack instead memory stack. The bug comes from the fact that user_stack_pointer() and current_user_stack_pointer() don't return the same register: ulong user_stack_pointer(struct pt_regs *regs) { return regs->ar_bspstore; } #define current_user_stack_pointer() (current_pt_regs()->r12) The change gets both back in sync. I think ptrace(PTRACE_GET_SYSCALL_INFO) is the only affected user by this bug on ia64. The change fixes 'rt_sigreturn.gen.test' strace test where it was observed initially. CC: Andrew Morton CC: Oleg Nesterov CC: linux-ia64@vger.kernel.org Bug: https://bugs.gentoo.org/769614 Reported-by: Dmitry V. Levin Signed-off-by: Sergei Trofimovich --- arch/ia64/include/asm/ptrace.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/ia64/include/asm/ptrace.h b/arch/ia64/include/asm/ptrace.h index b3aa46090101..08179135905c 100644 --- a/arch/ia64/include/asm/ptrace.h +++ b/arch/ia64/include/asm/ptrace.h @@ -54,8 +54,7 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs) { - /* FIXME: should this be bspstore + nr_dirty regs? */ - return regs->ar_bspstore; + return regs->r12; } static inline int is_syscall_success(struct pt_regs *regs) @@ -79,11 +78,6 @@ static inline long regs_return_value(struct pt_regs *regs) unsigned long __ip = instruction_pointer(regs); \ (__ip & ~3UL) + ((__ip & 3UL) << 2); \ }) -/* - * Why not default? Because user_stack_pointer() on ia64 gives register - * stack backing store instead... - */ -#define current_user_stack_pointer() (current_pt_regs()->r12) /* given a pointer to a task_struct, return the user's pt_regs */ # define task_pt_regs(t) (((struct pt_regs *) ((char *) (t) + IA64_STK_OFFSET)) - 1) -- 2.31.1