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 226C1C54EBD for ; Tue, 3 Jan 2023 15:23:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233401AbjACPXA (ORCPT ); Tue, 3 Jan 2023 10:23:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237757AbjACPWb (ORCPT ); Tue, 3 Jan 2023 10:22:31 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A459625F0; Tue, 3 Jan 2023 07:22:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=y1ul7efxZNAVNH9AU1USRVGMWta2/7di2SV8aglnj4o=; b=xMEN2rI6xG0UAfipPh0hKVsIlg TnH5O2c7xhrF8kY1cja6X/Cfa/Xp/rGZA3M1ITvuF7ldTXE9dnlxGh3sfMJ3ZljGwpL/PcLoMXcVW 5jJV3zSSG9JhLFxISjM+PpxkhZnvjDsTJ8D5i7gaqastxyqEzpNIhOlHwlKH/FIAnHDkL1QpKCTD2 +PeEvYFbL3NYuZFmachEM1lQyuhZuuMSnBuViDGrr7Zww4cjxHTdCSJGACjQIa9xni75OA42NY3R1 W1yGfyRHQ8CrNBEIAEPRl2J7pV0mTwb4RW5Ah1IlRTeGS3o17zNU+53opb67S04kiI+zF8JjpiXRb le8Z/U+Q==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:35940) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pCj7S-0005Um-LB; Tue, 03 Jan 2023 15:22:26 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1pCj7R-0002Aa-Lh; Tue, 03 Jan 2023 15:22:25 +0000 Date: Tue, 3 Jan 2023 15:22:25 +0000 From: "Russell King (Oracle)" To: Hector Martin Cc: Srinivas Kandagatla , Sven Peter , Alyssa Rosenzweig , asahi@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Eric Curtin Subject: Re: [PATCH v2] nvmem: core: Fix race in nvmem_register() Message-ID: References: <20230103114427.1825-1-marcan@marcan.st> <95a4cfde-490f-d26d-163e-7ab1400e7380@marcan.st> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 04, 2023 at 12:14:10AM +0900, Hector Martin wrote: > On 04/01/2023 00.06, Russell King (Oracle) wrote: > > Hi Hector, > > > > On Tue, Jan 03, 2023 at 10:48:52PM +0900, Hector Martin wrote: > >>>> @@ -822,11 +822,8 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) > >>>> break; > >>>> } > >>>> > >>>> - if (rval) { > >>>> - ida_free(&nvmem_ida, nvmem->id); > >>>> - kfree(nvmem); > >>>> - return ERR_PTR(rval); > >>>> - } > >>>> + if (rval) > >>>> + goto err_gpiod_put; > >>> > >>> Why was gpiod changes added to this patch, that should be a separate > >>> patch/discussion, as this is not relevant to the issue that you are > >>> reporting. > >> > >> Because freeing the device also does a gpiod_put in the destructor, so > >> doing this is correct in every other instance below and maintains > >> existing behavior, and it just so happens that this instance converges > >> into the same codepath so it is correct to merge it, and it just so > >> happens that the gpiod put was missing in this path to begin with so > >> this becomes a drive-by bugfix. > >> > >> If you don't like it I can remove it (i.e. reintroduce the bug for no > >> good reason) and you can submit this fix yourself, because I have no > >> incentive to waste time submitting a separate patch to fix a GPIO leak > >> in an error path corner case in a subsystem I don't own and I have much > >> bigger things to spend my (increasingly lower and lower) willingness to > >> fight for upstream submissions than this. > >> > >> Seriously, what is wrong with y'all kernel people. No other open source > >> project wastes contributors' time with stupid nitpicks like this. I > >> found a bug, I fixed it, I then fixed the issues you pointed out, and I > >> don't have the time nor energy to fight over this kind of nonsense next. > >> Do you want bugs fixed or not? > > > > This is not nonsense. We have always had a policy of one fix/change > > per patch, and in this case it makes complete and utter sense. Of > > course, the interpretation of "one change" is a matter of opinion. > > The change here is the race condition fix. That change involves adding > an error cleanup path that involves a gpio_put(). Therefore it seems > logical to actually use it in that one extra case that should've used it > anyway, a few lines above. The two are entirely unrelated. as I've already explained. The call to device_register() happens _after_ the check for rval from the dev_set_name() that you are changing. Moving device_register() doesn't make the lack of gpiod_put() any better or worse than it was before. That said, I'm now thinking that my patch is actually wrong, but for a different reason unrelated to the gpiod issue. :( -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!