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 7AE27CCA479 for ; Sun, 10 Jul 2022 22:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229543AbiGJW1o (ORCPT ); Sun, 10 Jul 2022 18:27:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbiGJW1m (ORCPT ); Sun, 10 Jul 2022 18:27:42 -0400 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2771EA1B4; Sun, 10 Jul 2022 15:27:41 -0700 (PDT) Date: Mon, 11 Jul 2022 06:28:46 +0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1657492059; 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=ZUFb5ucO1JJlddQkXqD+0kfsu3ItWuXMmHu5j+INC1Q=; b=laM9f48VefRkClFbhgfpIKhMHyWQu0k9ZxfIiwuQBKg701eA/tlpKG1C384CQnjzpiq1NE Rihkx2xXv2f5yzuri9JIArQ+ZlWPw6dPqYgI28M6ql98Fese0NFMBRgAkJUnBTtVyG6sqB rv33k2eZCqLAh34wY9FMIy2AldR15iU= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Tao Zhou To: Steven Rostedt Cc: Daniel Bristot de Oliveira , Wim Van Sebroeck , Guenter Roeck , Jonathan Corbet , Ingo Molnar , Thomas Gleixner , Peter Zijlstra , Will Deacon , Catalin Marinas , Marco Elver , Dmitry Vyukov , "Paul E. McKenney" , Shuah Khan , Gabriele Paoloni , Juri Lelli , Clark Williams , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-devel@vger.kernel.org, Tao Zhou Subject: Re: [PATCH V4 01/20] rv: Add Runtime Verification (RV) interface Message-ID: References: <60548902dbccaa7ba420e40e46835693e27f643f.1655368610.git.bristot@kernel.org> <20220710114242.745d65b3@rorschach.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220710114242.745d65b3@rorschach.local.home> X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 10, 2022 at 11:42:42AM -0400, Steven Rostedt wrote: > On Sun, 10 Jul 2022 23:11:43 +0800 > Tao Zhou wrote: > > > The @*pos of enable_monitors_start() can not be -1 or other negative value. > > And I checked that the *pos is 0(right?). That is safe. Sorry for not being > > that ture and maybe this is a notice here. Because if it is a negative value, > > the returned m_def is a point to a data place 16 bytes before &rv_monitors_list. > > That is a not ture rv_monitors_list stucture data. But it is not possiable now. > > Maybe "inspired" from your question. Look it more, I image this simulation. > > If the monitor(and all is enabled) is more enough to let the *pos to increase > > to -1. And the returned m_def is last monitor that returned from enable_monitors_start(). > > The enable_monitors_next() check from the last monitor and return NULL. > > Only show the last monitor. This will not really happen I think. > > But I am not focus enough to the seq file code or others now, so this may be > > more possible to be not right. Late reply continued from me.. > > > So basically you are saying we should have: > > > +static void *enabled_monitors_start(struct seq_file *m, loff_t *pos) > > +{ > > + struct rv_monitor_def *m_def; > > + loff_t l; > > + > > + mutex_lock(&rv_interface_lock); > > if (list_empty(&rv_monitors_list->list)) > return NULL; > ? >From the function itself, this looks safer. Thanks. > Probably safer to have that. > > -- Steve > > > > + m_def = list_entry(&rv_monitors_list, struct rv_monitor_def, list); > > + > > + for (l = 0; l <= *pos; ) { > > + m_def = enabled_monitors_next(m, m_def, &l); > > + if (!m_def) > > + break; > > + } > > + > > + return m_def; > > +}