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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 F3D66C4360C for ; Thu, 10 Oct 2019 08:37:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C3E6C20B7C for ; Thu, 10 Oct 2019 08:37:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570696668; bh=ADigWx33rF4XyHxIEKHsXdqfJMUHpqFwLSqHQEu0hVc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0OxC7MjsUQvoTRXI4CxcLoIJonZV39SA8+6ymNXVap/fQGmkcNW9lQHVM8kT5dirq 0j9WCX0rqYib3/nH0GikGa6J9wt7c3JTQ0090Bk/pnAnw6jc9mE7IoGHIe5fij8bEA oadbIcmsuj5OFDNI3bcV3qtC7c6LCc3GZcO3Z1uU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733225AbfJJIhr (ORCPT ); Thu, 10 Oct 2019 04:37:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:40424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728388AbfJJIhr (ORCPT ); Thu, 10 Oct 2019 04:37:47 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E0BD20B7C; Thu, 10 Oct 2019 08:37:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570696666; bh=ADigWx33rF4XyHxIEKHsXdqfJMUHpqFwLSqHQEu0hVc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jNEyCt2P73zS+2K4y/4+/eup+SEKoEV/KLsYrJuBg/lJHvrTLzyCHejeSPFlaHoor h9sgExYpUu1nMBSGOseJD+QfYR54DlUcV0fjsL0bBj2erADG/MlFO8Iv9FcgxAJgFk oFbwedJESpwE3NnDxochzSlBC5UVNGdLrInQUsY4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ilya Leoshkevich , Vasily Gorbik Subject: [PATCH 5.3 001/148] s390/process: avoid potential reading of freed stack Date: Thu, 10 Oct 2019 10:34:22 +0200 Message-Id: <20191010083609.882111313@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191010083609.660878383@linuxfoundation.org> References: <20191010083609.660878383@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vasily Gorbik commit 8769f610fe6d473e5e8e221709c3ac402037da6c upstream. With THREAD_INFO_IN_TASK (which is selected on s390) task's stack usage is refcounted and should always be protected by get/put when touching other task's stack to avoid race conditions with task's destruction code. Fixes: d5c352cdd022 ("s390: move thread_info into task_struct") Cc: stable@vger.kernel.org # v4.10+ Acked-by: Ilya Leoshkevich Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/process.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -184,20 +184,30 @@ unsigned long get_wchan(struct task_stru if (!p || p == current || p->state == TASK_RUNNING || !task_stack_page(p)) return 0; + + if (!try_get_task_stack(p)) + return 0; + low = task_stack_page(p); high = (struct stack_frame *) task_pt_regs(p); sf = (struct stack_frame *) p->thread.ksp; - if (sf <= low || sf > high) - return 0; + if (sf <= low || sf > high) { + return_address = 0; + goto out; + } for (count = 0; count < 16; count++) { sf = (struct stack_frame *) sf->back_chain; - if (sf <= low || sf > high) - return 0; + if (sf <= low || sf > high) { + return_address = 0; + goto out; + } return_address = sf->gprs[8]; if (!in_sched_functions(return_address)) - return return_address; + goto out; } - return 0; +out: + put_task_stack(p); + return return_address; } unsigned long arch_align_stack(unsigned long sp)