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 A5B98C433F5 for ; Fri, 25 Feb 2022 10:20:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239454AbiBYKUx (ORCPT ); Fri, 25 Feb 2022 05:20:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47078 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238179AbiBYKUu (ORCPT ); Fri, 25 Feb 2022 05:20:50 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70D1A1C233E for ; Fri, 25 Feb 2022 02:20:17 -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 sin.source.kernel.org (Postfix) with ESMTPS id 77BC8CE2429 for ; Fri, 25 Feb 2022 10:20:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7C55C340E7; Fri, 25 Feb 2022 10:20:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645784413; bh=jTN6lFqaS32dJ2UbgZGYAvzDkSeCb/06dnDC06bxVD8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qht9oQi/uwHy7zPXb1T63ftiT8u3kdL+ml2WdA6QCIN2LCEdqMWQBz+K17pIwhOka Zpk5SCUwFxIkzkGhkM8LUZ/3Ot7BB+0CemetqOxR7+7ma7CuMkEhSzizYBdg5RZ5mJ a7r6fbeHinrLavoEc5YGchz7ww9VK0nzCjrHFdey6SVT04DBr8vnPBOTpIecs5fDLu f3EWyNx1Z1xLXQRT/wrF4pl4PX9DHM+sqrcMEc/BwD0iyhYR5MAhoUZ8yqZAiuuv/x W2yZL//0n8HHs1Ubvb3bBf6CvzWVg7uB/b3m5Lvw1UctgX9+ky7Z3dSRbYitxEmlzd 4GBGEyr+AIS/Q== Date: Fri, 25 Feb 2022 19:20:08 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: Peter Zijlstra , x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com, jpoimboe@redhat.com, andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org, ndesaulniers@google.com, keescook@chromium.org, samitolvanen@google.com, mark.rutland@arm.com, alyssa.milburn@intel.com, mbenes@suse.cz, alexei.starovoitov@gmail.com Subject: Re: [PATCH v2 12/39] x86/ibt,ftrace: Search for __fentry__ location Message-Id: <20220225192008.d7a4f2b5558fe43c95909777@kernel.org> In-Reply-To: <20220224211919.0612a3f6@rorschach.local.home> References: <20220224145138.952963315@infradead.org> <20220224151322.714815604@infradead.org> <20220225005520.c69be2fbdbd28028361792d9@kernel.org> <20220224105847.5c899324@gandalf.local.home> <20220225103449.6084e5314273556f35107cd9@kernel.org> <20220224211919.0612a3f6@rorschach.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; 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 Thu, 24 Feb 2022 21:19:19 -0500 Steven Rostedt wrote: > On Fri, 25 Feb 2022 10:34:49 +0900 > Masami Hiramatsu wrote: > > > > > > + if (!rec) { > > > > > + if (!kallsyms_lookup_size_offset(ip, &size, &offset)) > > > > > + goto out; > > > > > + > > > > > + if (!offset) > > > > > > > > Isn't this 'if (offset)' ? > > > > > > No, the point to only look for the fentry location if the ip passed in > > > points to the start of the function. IOW, +0 offset. > > > > OK, so this means ftrace_location() will be same as > > ftrace_location_range(sym, sym_end) ? > > No. It only acts like ftrace_location_range(sym, sym_end) if the passed > in argument is the ip of the function (kallsyms returns offset = 0) Got it. So now ftrace_location() will return the ftrace address when the ip == func or ip == mcount-call. Thank you, -- Masami Hiramatsu