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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no 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 B071BC433E0 for ; Tue, 7 Jul 2020 16:02:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EF5E20738 for ; Tue, 7 Jul 2020 16:02:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728316AbgGGQCS (ORCPT ); Tue, 7 Jul 2020 12:02:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:60852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727793AbgGGQCQ (ORCPT ); Tue, 7 Jul 2020 12:02:16 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 447E920674; Tue, 7 Jul 2020 16:02:14 +0000 (UTC) Date: Tue, 7 Jul 2020 12:02:12 -0400 From: Steven Rostedt To: Masahiro Yamada Cc: linux-kbuild@vger.kernel.org, Ingo Molnar , Anders Roxell , Sami Tolvanen , Brendan Higgins , "David S. Miller" , Haren Myneni , Herbert Xu , Jiri Kosina , Joe Lawrence , Josh Poimboeuf , Miroslav Benes , Petr Mladek , Tal Gilboa , kunit-dev@googlegroups.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [PATCH v2 2/2] kbuild: trace functions in subdirectories of lib/ Message-ID: <20200707120212.7010fa4f@oasis.local.home> In-Reply-To: <20200707092117.963394-2-masahiroy@kernel.org> References: <20200707092117.963394-1-masahiroy@kernel.org> <20200707092117.963394-2-masahiroy@kernel.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Tue, 7 Jul 2020 18:21:17 +0900 Masahiro Yamada wrote: > ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE) > > exists here in sub-directories of lib/ to keep the behavior of > commit 2464a609ded0 ("ftrace: do not trace library functions"). > > Since that commit, not only the objects in lib/ but also the ones in > the sub-directories are excluded from ftrace (although the commit > description did not explicitly mention this). > > However, most of library functions in sub-directories are not so hot. > Re-add them to ftrace. I'm OK with this change, but note, it wasn't just the hot path that I disabled ftrace on lib for, but some of these calls are done very early at boot up. It may have been PowerPC that I was stumbling over. The issue is that they would call mcount before the kernel was mapped properly, and the system would crash. My PowerPC box no longer boots so I can't test this anymore. But a lot has changed since 2008, and all this may very well be OK. -- Steve