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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CCB3C433EF for ; Wed, 24 Nov 2021 13:02:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346364AbhKXNF7 (ORCPT ); Wed, 24 Nov 2021 08:05:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:41104 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347996AbhKXNDr (ORCPT ); Wed, 24 Nov 2021 08:03:47 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8F48061A3F; Wed, 24 Nov 2021 12:36:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637757407; bh=/o8rmn2R0cPjyvnhh+SXEnJPg9vRIPkvzndQ8Xv5ydg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N8S9eHQk4CtMnrvnRGSy1M39hiJ/2YaiVworsJJ09ImoWPMF5FTjz4XKNn0MKwkaN 0SCgG/PYXO4nEO9/uKv7BPPEmq8EXgpfc+pm+3WaLB2cyrbQToP9XDVZ25pzMEz7oi MyHEuAah15UB7onZsNJ9N8pikajEObxl2PKaCNuk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Helge Deller , Sasha Levin Subject: [PATCH 4.19 124/323] task_stack: Fix end_of_stack() for architectures with upwards-growing stack Date: Wed, 24 Nov 2021 12:55:14 +0100 Message-Id: <20211124115723.128578826@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115718.822024889@linuxfoundation.org> References: <20211124115718.822024889@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 6a841929073f9..4f099d3fed3a9 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