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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BF3CC4332F for ; Fri, 9 Dec 2022 21:51:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229951AbiLIVvt (ORCPT ); Fri, 9 Dec 2022 16:51:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44550 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbiLIVvq (ORCPT ); Fri, 9 Dec 2022 16:51:46 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 026D3389ED for ; Fri, 9 Dec 2022 13:51:46 -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 ams.source.kernel.org (Postfix) with ESMTPS id 67EF2B82918 for ; Fri, 9 Dec 2022 21:51:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29DA3C433EF; Fri, 9 Dec 2022 21:51:42 +0000 (UTC) Date: Fri, 9 Dec 2022 16:51:39 -0500 From: Steven Rostedt To: Mark Rutland Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, will@kernel.org, samitolvanen@google.com, keescook@chromium.org, mhiramat@kernel.org Subject: Re: [PATCH] ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack Message-ID: <20221209165139.37d033ee@gandalf.local.home> In-Reply-To: References: <20221209143402.3332369-1-ardb@kernel.org> 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 9 Dec 2022 14:40:25 +0000 Mark Rutland wrote: > On Fri, Dec 09, 2022 at 03:34:02PM +0100, Ard Biesheuvel wrote: > > The recent switch on arm64 from DYNAMIC_FTRACE_WITH_REGS to > > DYNAMIC_FTRACE_WITH_ARGS failed to take into account that we currently > > require the former in order to allow the function graph tracer to be > > enabled in combination with shadow call stacks. This means that this is > > no longer permitted at all, in spite of the fact that either flavour of > > ftrace works perfectly fine in this combination. > > > > Given that arm64 is the only arch that implements shadow call stacks in > > the first place, let's update the condition to just reflect the arm64 > > change. When other architectures adopt shadow call stack support, this > > can be revisited if needed. > > > > Signed-off-by: Ard Biesheuvel > > My bad; sorry about this, and thanks for the fix! > > Acked-by: Mark Rutland > > We should probably also add: > > Fixes: 26299b3f6ba26bfc ("ftrace: arm64: move from REGS to ARGS") Actually, I believe it is: Fixes: ddc9863e9e90 ("scs: Disable when function graph tracing is enabled") As according to the comments, scs is broken with function graph unless function graph is using the ftrace mechanism. And that is only true if WITH_ARGS is set, not REGS. Acked-by: Steven Rostedt (Google) -- Steve