Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87F9BC433EF for ; Mon, 15 Nov 2021 17:51:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71DBC632AF for ; Mon, 15 Nov 2021 17:51:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238689AbhKORyv (ORCPT ); Mon, 15 Nov 2021 12:54:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:50840 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237778AbhKORYD (ORCPT ); Mon, 15 Nov 2021 12:24:03 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C7E6960F22; Mon, 15 Nov 2021 17:17:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636996632; bh=THe/nioCgVCQvo/WlreBJb3rdIBvO7XNaQf2Ui04Ou8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z+9QGMMhqmBHbM43SG9DBj/yDp6EoD8yCAvvp0G7qEmxva3y2A4/VlszWVo0U5/gI GhZy661ASFjgPfP40F65KsAcsfX/r7qjr0zq7ANGpAp2FMlpzqDg7mUMIuDYvYDxGa 0VX3hcbbc2jHPdKwZNv78EKrIlWrvM96QSIapY8k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Helge Deller , Sasha Levin Subject: [PATCH 5.4 177/355] task_stack: Fix end_of_stack() for architectures with upwards-growing stack Date: Mon, 15 Nov 2021 18:01:41 +0100 Message-Id: <20211115165319.511324574@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165313.549179499@linuxfoundation.org> References: <20211115165313.549179499@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: linux-kernel@vger.kernel.org From: Helge Deller [ Upstream commit 9cc2fa4f4a92ccc6760d764e7341be46ee8aaaa1 ] The function end_of_stack() returns a pointer to the last entry of a stack. For architectures like parisc where the stack grows upwards return the pointer to the highest address in the stack. Without this change I faced a crash on parisc, because the stackleak functionality wrote STACKLEAK_POISON to the lowest address and thus overwrote the first 4 bytes of the task_struct which included the TIF_FLAGS. Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- include/linux/sched/task_stack.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/sched/task_stack.h b/include/linux/sched/task_stack.h index 2413427e439c7..d10150587d819 100644 --- a/include/linux/sched/task_stack.h +++ b/include/linux/sched/task_stack.h @@ -25,7 +25,11 @@ static inline void *task_stack_page(const struct task_struct *task) static inline unsigned long *end_of_stack(const struct task_struct *task) { +#ifdef CONFIG_STACK_GROWSUP + return (unsigned long *)((unsigned long)task->stack + THREAD_SIZE) - 1; +#else return task->stack; +#endif } #elif !defined(__HAVE_THREAD_FUNCTIONS) -- 2.33.0