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 21BA2ECAAA3 for ; Fri, 26 Aug 2022 21:14:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231645AbiHZVOF (ORCPT ); Fri, 26 Aug 2022 17:14:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231247AbiHZVOE (ORCPT ); Fri, 26 Aug 2022 17:14:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E562E58A9; Fri, 26 Aug 2022 14:14:03 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 858B161F68; Fri, 26 Aug 2022 21:14:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A498DC433C1; Fri, 26 Aug 2022 21:14:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661548442; bh=7azrnsiCu14tEupZXXCpNTjljV0a/zloctCANgEak44=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=kjbW75aBgkj/vd6Em/TorngQ+aIIuyl75Eb8oCububNQSjqk5bAkw8bPWCIqMYZfs 09mAnflYPx+wM4D/DxksBBmfbTwIeyE4d36g3JSRF1V7qF+piTggxa2qdyhxNjejgQ gByqr/PuEZUWmYej2JmeJz9UfMk0m0L02ljQZSOGOWstnPXjI1KDBnhOjQ9zPiHkXT MRd4QcujuEV9qqi6F1jaSJ3cHHV69KNLkQbEVt4vnXTJPHmmsHVRQz/lT9lrSEv+vo VNiz8SlsYFBgKDOCeOUfLXR5ZtpBhsTMYCpaQ1rNy1nXxLeld/UCTZLKA9NyJ6w7p9 JsxBDYm6A8Nmw== Date: Fri, 26 Aug 2022 16:14:01 -0500 From: Bjorn Helgaas To: Yang Yingliang Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, bhelgaas@google.com, Rob Herring Subject: Re: [PATCH -next 1/3] PCI: fix double put_device() in error case in pci_create_root_bus() Message-ID: <20220826211401.GA2959769@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220825122753.1838930-1-yangyingliang@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+cc Rob] On Thu, Aug 25, 2022 at 08:27:51PM +0800, Yang Yingliang wrote: > If device_add() fails in pci_register_host_bridge(), the brigde device will > be put once, and it will be put again in error path of pci_create_root_bus(). > Move the put_device() from pci_create_root_bus() to pci_register_host_bridge() > to fix this problem. And use device_unregister() instead of del_device() and > put_device(). s/brigde/bridge/ > Fixes: 9885440b16b8 ("PCI: Fix pci_host_bridge struct device release/free handling") If you're fixing a commit from somebody else, please always cc: the author because the author can help review the change. > Signed-off-by: Yang Yingliang > --- > drivers/pci/probe.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index c5286b027f00..e500eb9d6468 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1027,7 +1027,7 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) > > unregister: > put_device(&bridge->dev); > - device_del(&bridge->dev); > + device_unregister(&bridge->dev); I don't understand this part. device_unregister() looks like this: void device_unregister(struct device *dev) { device_del(dev); put_device(dev); } So this calls put_device(&bridge->dev) twice, doesn't it? The "unregister" label looks poorly named. We only get there if device_register() *failed*. We shouldn't need to unregister anything in that case. > free: > kfree(bus); > @@ -3037,13 +3037,9 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus, > > error = pci_register_host_bridge(bridge); > if (error < 0) > - goto err_out; > + return NULL; > > return bridge->bus; > - > -err_out: > - put_device(&bridge->dev); > - return NULL; This part looks right to me. The get_device() is in pci_register_host_bridge(), and if pci_register_host_bridge() returns failure, I think it should first do the corresponding put_device(). > } > EXPORT_SYMBOL_GPL(pci_create_root_bus); > > -- > 2.25.1 >