Received: by 2002:a05:6a10:1a4d:0:0:0:0 with SMTP id nk13csp6032364pxb; Mon, 14 Feb 2022 13:35:34 -0800 (PST) X-Google-Smtp-Source: ABdhPJz07/Sf+opPYyZdDxErw1imxw26Zve3RsYUqRNKv3xOEY7Zd+DW84Yoyzj3zCUcsdQuquOl X-Received: by 2002:a17:902:f787:: with SMTP id q7mr1033147pln.120.1644874534602; Mon, 14 Feb 2022 13:35:34 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1644874534; cv=none; d=google.com; s=arc-20160816; b=Map9zNrLLrhoCEG3ag3k2NM7hSQgk2Zd1vBmJ89Ko2mCzzJIcgNyHjZTCtb5Ss87GT 15s3fHQyk+IcByL4GpeAnUCw5zh4E1J573NBhFeN9iInHKq7gzR73kvpt5El2mDqVksE Fe2FUKLJag8fzlKpbkZYCCytvX1tb513cmLwR2kCX6MYsSPUR1yHd1lcn2+a48932giY oUliqHYdjUY6OhgG/VrDmvZYCulPo2uYknigbfAbUAXhcl9msVbpRVOyj9sDG9zM7tPp AKRUwI/n0S2POEtDCWw7cd9WGy2p5zScpGJM3JTk95kqvWh5bJuUU/tHS4cDxz5ySgVz 7Xuw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date; bh=punPKbH/3lczY6BRfiEu7dtgKyxeA6oLbxBc2j/ZySM=; b=nLr4yFOOLJVkh7A20RUJFY8bTy60++HnJKHf3cyik1J+nQVBgqCVLrofkMEWkH/gns q2xiRaavBHBHJ+DbK61YrrgYk9TyoXT7j0v0Fr2Yixnpy9rXdGoKWC16x5lmiDnXuJLq B9mbKclslFDkKGuQkZITOIiwMdaSSYR8HLGIqO+M2tiTqZJ7U0pm/pqPby7I9U4jxVsm C196falW77NhiilgPUL0TEmMHFFdAWnZL5sN3q3BLwgLM54P3WfN8MOwyrbGvtxaOous 7LhJKnjJLcxjyxxJ5gttEvWQJ1qoqxT3ROI4oQt5UO3ixXDHwHpylEC172yNsGGUG1oo /CfA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id z6si14845588plg.174.2022.02.14.13.35.17; Mon, 14 Feb 2022 13:35:34 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231419AbiBNVen (ORCPT + 99 others); Mon, 14 Feb 2022 16:34:43 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:34036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231359AbiBNVdo (ORCPT ); Mon, 14 Feb 2022 16:33:44 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B8AC156941; Mon, 14 Feb 2022 13:31:09 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2CEAE60FEB; Mon, 14 Feb 2022 19:03:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68A09C340E9; Mon, 14 Feb 2022 19:03:05 +0000 (UTC) Date: Mon, 14 Feb 2022 14:03:04 -0500 From: Steven Rostedt To: "Naveen N. Rao" Cc: Christophe Leroy , Jiri Kosina , Joe Lawrence , Josh Poimboeuf , Miroslav Benes , Ingo Molnar , Petr Mladek , "linux-kernel@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "live-patching@vger.kernel.org" Subject: Re: [PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller Message-ID: <20220214140304.04d1e8a8@gandalf.local.home> In-Reply-To: <1644859156.qdgqumennn.naveen@linux.ibm.com> References: <04d196585ff81bde06a000bd9c633a33a5b21130.1640017960.git.christophe.leroy@csgroup.eu> <1644859156.qdgqumennn.naveen@linux.ibm.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 14 Feb 2022 22:54:23 +0530 "Naveen N. Rao" wrote: > For x86, commit 0c0593b45c9b4e ("x86/ftrace: Make function graph use > ftrace directly") also adds recursion check before the call to > function_graph_enter() in prepare_ftrace_return(). Do we need that on > powerpc as well? Yes. The function_graph_enter() does not provide any recursion protection, so if it were to call something that gets function graph traced, it will crash the machine. -- Steve