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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 08723C55ABD for ; Fri, 6 Nov 2020 13:13:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9CCE5206FA for ; Fri, 6 Nov 2020 13:13:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="M+tR/rKx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727346AbgKFNNV (ORCPT ); Fri, 6 Nov 2020 08:13:21 -0500 Received: from mx2.suse.de ([195.135.220.15]:57040 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727169AbgKFNNV (ORCPT ); Fri, 6 Nov 2020 08:13:21 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604668398; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/qFlNeW+fj9kPag6iPvAKbxfuQxHVIdXyO+NAnfQv1k=; b=M+tR/rKxslTPuT6FfxTzbpuuxYbiZZG3CnqFYk93k8am/VLmSymRvyUiwOy4Hr5waPoLce uQiZvPathsmCgazo7IfORam7PuE22q5xJHq/iNivwhCmxch4+MaufWlLk/oXEAcDNCMlcc x3wJTN1WOECehMoqwdLrqgU3bZ/wBxo= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6BB69AB8F; Fri, 6 Nov 2020 13:13:18 +0000 (UTC) Date: Fri, 6 Nov 2020 14:13:17 +0100 From: Petr Mladek To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Masami Hiramatsu , Andrew Morton , Peter Zijlstra , Ingo Molnar , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Jonathan Corbet , Guo Ren , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Thomas Gleixner , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Kees Cook , Anton Vorontsov , Colin Cross , Tony Luck , Joe Lawrence , Kamalesh Babulal , Mauro Carvalho Chehab , Sebastian Andrzej Siewior , linux-doc@vger.kernel.org, linux-csky@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [PATCH 11/11 v3] ftrace: Add recording of functions that caused recursion Message-ID: <20201106131317.GW20201@alley> References: <20201106023235.367190737@goodmis.org> <20201106023548.102375687@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201106023548.102375687@goodmis.org> Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Thu 2020-11-05 21:32:46, Steven Rostedt wrote: > From: "Steven Rostedt (VMware)" > > This adds CONFIG_FTRACE_RECORD_RECURSION that will record to a file > "recursed_functions" all the functions that caused recursion while a > callback to the function tracer was running. > > Changes since v2: > > - Use trace_recursion flags in current for protecting recursion of recursion recording > - Make the recursion logic a little cleaner > - Export GPL the recursion recording JFYI, the code reading and writing the cache looks good to me. It is still possible that some entries might stay unused (filled with zeroes) but it should be hard to hit in practice. It is good enough from my POV. I do not give Reviewed-by tag just because I somehow do not have power to review the entire patch carefully enough at the moment. Best Regards, Petr