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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 93B6AC10F11 for ; Wed, 10 Apr 2019 11:10:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F0742229F for ; Wed, 10 Apr 2019 11:10:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730833AbfDJLFd (ORCPT ); Wed, 10 Apr 2019 07:05:33 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:58702 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730756AbfDJLFb (ORCPT ); Wed, 10 Apr 2019 07:05:31 -0400 Received: from localhost ([127.0.0.1] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1hEB2m-00050z-Qr; Wed, 10 Apr 2019 13:05:28 +0200 Message-Id: <20190410103643.750954603@linutronix.de> User-Agent: quilt/0.65 Date: Wed, 10 Apr 2019 12:27:56 +0200 From: Thomas Gleixner To: LKML Cc: Josh Poimboeuf , x86@kernel.org, Andy Lutomirski , Steven Rostedt , Alexander Potapenko Subject: [RFC patch 02/41] x86/stacktrace: Remove the pointless ULONG_MAX marker References: <20190410102754.387743324@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Terminating the last trace entry with ULONG_MAX is a completely pointless exercise and none of the consumers can rely on it because it's inconsistently implemented across architectures. In fact quite some of the callers remove the entry and adjust stack_trace.nr_entries afterwards. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/stacktrace.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) --- a/arch/x86/kernel/stacktrace.c +++ b/arch/x86/kernel/stacktrace.c @@ -46,9 +46,6 @@ static void noinline __save_stack_trace( if (!addr || save_stack_address(trace, addr, nosched)) break; } - - if (trace->nr_entries < trace->max_entries) - trace->entries[trace->nr_entries++] = ULONG_MAX; } /* @@ -97,7 +94,7 @@ static int __always_inline if (regs) { /* Success path for user tasks */ if (user_mode(regs)) - goto success; + return 0; /* * Kernel mode registers on the stack indicate an @@ -132,10 +129,6 @@ static int __always_inline if (!(task->flags & (PF_KTHREAD | PF_IDLE))) return -EINVAL; -success: - if (trace->nr_entries < trace->max_entries) - trace->entries[trace->nr_entries++] = ULONG_MAX; - return 0; } @@ -221,9 +214,6 @@ void save_stack_trace_user(struct stack_ /* * Trace user stack if we are not a kernel thread */ - if (current->mm) { + if (current->mm) __save_stack_trace_user(trace); - } - if (trace->nr_entries < trace->max_entries) - trace->entries[trace->nr_entries++] = ULONG_MAX; }