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 7DDD6C4332F for ; Sun, 6 Nov 2022 03:05:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229614AbiKFDFX (ORCPT ); Sat, 5 Nov 2022 23:05:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbiKFDFV (ORCPT ); Sat, 5 Nov 2022 23:05:21 -0400 Received: from mail3-relais-sop.national.inria.fr (mail3-relais-sop.national.inria.fr [192.134.164.104]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C9551056C for ; Sat, 5 Nov 2022 20:05:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=inria.fr; s=dc; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=ripiz7bquHA2oeLd16o4nKtQ6i8/6mTwp8aDeJG4/NQ=; b=IpB0KYZF0D6SosB0CDleU4eiWgeHZ+23yZvVRVgkAxFPwSFQVRujHzrJ ddrmxVt9Gg3epIJLulMpw2WuMUr81faR590sA9Dqtd/xDMZ+chsGPC4bD cyel2JWbsLCO0b5npswMcQHnvsmImPxWC5KbkcOog19uqSOGlm23udsiE E=; Authentication-Results: mail3-relais-sop.national.inria.fr; dkim=none (message not signed) header.i=none; spf=SoftFail smtp.mailfrom=julia.lawall@inria.fr; dmarc=fail (p=none dis=none) d=inria.fr X-IronPort-AV: E=Sophos;i="5.96,141,1665439200"; d="scan'208";a="38549807" Received: from unknown (HELO hadrien) ([129.126.215.52]) by mail3-relais-sop.national.inria.fr with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2022 04:05:16 +0100 Date: Sun, 6 Nov 2022 11:05:14 +0800 (+08) From: Julia Lawall To: Steven Rostedt cc: Linus Torvalds , linux-kernel@vger.kernel.org, Thomas Gleixner , Stephen Boyd , Guenter Roeck , Anna-Maria Gleixner , Andrew Morton Subject: Re: [PATCH v4a 00/38] timers: Use timer_shutdown*() before freeing timers In-Reply-To: <20221105203634.7e0b2e8e@rorschach.local.home> Message-ID: References: <20221105060024.598488967@goodmis.org> <20221105123642.596371c7@rorschach.local.home> <20221105140356.6a3da628@rorschach.local.home> <20221105144303.3552bf85@rorschach.local.home> <775ada-29f1-3b56-7deb-c1b8d958e2c@inria.fr> <20221105203634.7e0b2e8e@rorschach.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 5 Nov 2022, Steven Rostedt wrote: > On Sun, 6 Nov 2022 07:08:48 +0800 (+08) > Julia Lawall wrote: > > > Various suggestions: > > > > 1. On your ... put when strict and then on a separate line put when != > > ptr. The when strict will get rid of the goto problem (usually a > > desirable feature, but not here) and the when != ptr will be sure that ptr > > is not used before the free. > > You mean ptr->timer.function? because it's allowed to be touched. Only > this case is weird (and I believe I covered it). > > Not sure what you mean by "put when strict" I added: > > ... when strict > > Thinking that's what you meant (examples would be easier to understand, > than descriptions). And it didn't cover the return case. Does it only > cover gotos? > > See drivers/net/wireless/intel/iwlwifi/mvm/sta.c for the false positive case: > > del_timer_sync(&baid_data->session_timer); > [..] But there is a kfree_rcu(baid_data, rcu_head); right below. So it looks fine? julia > return 0; > > out_free: > kfree(baid_data); > return ret; > } > > That "return 0" should make the match fail. > > > > > 2. If you want to handle the initialization of the function field, then > > you can duplicate the rule and add the removal of that assignment in the > > first one. This only seems worth it if it is a very common case. > > Otherwise, I would agree with Linus and just take care of it by hand > > later. > > No, Linus wants the script to not touch the initialization case. That > is, currently, the script does the conversion (which also initializes > it), and the timer.function = NULL is just redundant. > > What Linus wanted, was my script to do nothing in this case. But I > figured this part out. > > > > > 3. Running the rule three times seems to me like a reasonable choice. Or > > you could duplicate the rule three times. But that would be more script > > to read through. If this is not a common case, though, you could probably > > also fix the one up later by hand. > > Yeah, that's fine. > > I'm just looking for how to avoid the goto / return case. > > -- Steve >