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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 E8A16C43461 for ; Thu, 15 Apr 2021 14:51:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5843613BA for ; Thu, 15 Apr 2021 14:51:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233685AbhDOOvd (ORCPT ); Thu, 15 Apr 2021 10:51:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:37632 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232767AbhDOOu4 (ORCPT ); Thu, 15 Apr 2021 10:50:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 01D386113B; Thu, 15 Apr 2021 14:50:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498232; bh=y7Cv+OVHuX4wPsXxP2+C6mwyl21cXJ8vYFpW84dFT1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hheCZu9b8PZSXZm9PFxl31W/3NOjUb8D2UxR5BW5s05np8NI6bUZ94ybyj28y4UIT Sh1udGRNSVNgOfctOyonC8nT5xl2SX/G5hOzBDCoZaYrXPn5/jMN/mfkWtuy02xCXV BzjWKv5Fk/a8xFV474zbK7vxQlXMgFKScD22u7DM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sergei Trofimovich , "Dmitry V. Levin" , Oleg Nesterov , Andrew Morton , Linus Torvalds Subject: [PATCH 4.9 11/47] ia64: fix user_stack_pointer() for ptrace() Date: Thu, 15 Apr 2021 16:47:03 +0200 Message-Id: <20210415144413.836396126@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144413.487943796@linuxfoundation.org> References: <20210415144413.487943796@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sergei Trofimovich commit 7ad1e366167837daeb93d0bacb57dee820b0b898 upstream. ia64 has two stacks: - memory stack (or stack), pointed at by by r12 - register backing store (register stack), pointed at by ar.bsp/ar.bspstore with complications around dirty register frame on CPU. In [1] Dmitry noticed that PTRACE_GET_SYSCALL_INFO returns the 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. Link: https://bugs.gentoo.org/769614 [1] Link: https://lkml.kernel.org/r/20210331084447.2561532-1-slyfox@gentoo.org Signed-off-by: Sergei Trofimovich Reported-by: Dmitry V. Levin Cc: Oleg Nesterov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/ia64/include/asm/ptrace.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) --- a/arch/ia64/include/asm/ptrace.h +++ b/arch/ia64/include/asm/ptrace.h @@ -53,8 +53,7 @@ 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) @@ -78,11 +77,6 @@ static inline long regs_return_value(str 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)