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=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 A7993C43387 for ; Fri, 21 Dec 2018 17:58:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B1D5218E0 for ; Fri, 21 Dec 2018 17:58:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391324AbeLUR6L (ORCPT ); Fri, 21 Dec 2018 12:58:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:55956 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391145AbeLUR46 (ORCPT ); Fri, 21 Dec 2018 12:56:58 -0500 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (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 323DC2192D; Fri, 21 Dec 2018 17:56:58 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.91) (envelope-from ) id 1gaP2f-0002MJ-8H; Fri, 21 Dec 2018 12:56:57 -0500 Message-Id: <20181221175657.149883677@goodmis.org> User-Agent: quilt/0.65 Date: Fri, 21 Dec 2018 12:56:29 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Namhyung Kim , Masami Hiramatsu , James Morse Subject: [for-next][PATCH 11/24] tracing: Fix ftrace_graph_get_ret_stack() to use task and not current References: <20181221175618.968519903@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" The function ftrace_graph_get_ret_stack() takes a task struct descriptor but uses current as the task to perform the operations on. In pretty much all cases the task decriptor is the same as current, so this wasn't an issue. But there is a case in the ARM architecture that passes in a task that is not current, and expects a result from that task, and this code breaks it. Fixes: 51584396cff5 ("arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack") Reported-by: James Morse Tested-by: James Morse Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/fgraph.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index d4f04f0ca646..8dfd5021b933 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -246,10 +246,10 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer) struct ftrace_ret_stack * ftrace_graph_get_ret_stack(struct task_struct *task, int idx) { - idx = current->curr_ret_stack - idx; + idx = task->curr_ret_stack - idx; if (idx >= 0 && idx <= task->curr_ret_stack) - return ¤t->ret_stack[idx]; + return &task->ret_stack[idx]; return NULL; } -- 2.19.2