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 D897EECAAD4 for ; Fri, 26 Aug 2022 22:38:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235837AbiHZWiQ (ORCPT ); Fri, 26 Aug 2022 18:38:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231216AbiHZWiP (ORCPT ); Fri, 26 Aug 2022 18:38:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4A32E68D6; Fri, 26 Aug 2022 15:38:14 -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 ams.source.kernel.org (Postfix) with ESMTPS id 7375AB83342; Fri, 26 Aug 2022 22:38:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2097C433C1; Fri, 26 Aug 2022 22:38:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661553492; bh=2x8oP1av/GgT8wp1V9gUhZRtYrQh72Wv7er/tjyinjY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=ALuZPJWezJXRb3tYWtqYGTLy6XeWMSS4Vq8DUkpHSm9lZPvL6w988PTfJN779hiKH okGVloewqOtEkX2cE2Osvtrpc5LAAW8KXfswXk4m4mnKQzShUzD7me7KeLLrQx3feA 46cnW2wwoEABzc6ThPnVEk0aPXpB3K6vBiJcx+Im3YTEWpbZpeKFafeTNKrv7eFHiD 24rE1LRk2UcBxAOufVNnKZOLgXg9jI+hES0H8YYj9Q5sm6/uIj6cxzQ07zNVVrpUr7 XQZqK38+/pdBJmhaffDINEUB/yOju2oAKDVY/3ISuApnAYaMni5s9tGWA3zyxxgxzg gkdKHyBd9rdOg== Date: Fri, 26 Aug 2022 17:38:10 -0500 From: Bjorn Helgaas To: Yang Yingliang Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, bhelgaas@google.com, Arnd Bergmann , Rob Herring Subject: Re: [PATCH -next 2/3] PCI: fix possible memory leak in error case in pci_register_host_bridge() Message-ID: <20220826223810.GA2961041@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220825122753.1838930-2-yangyingliang@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+cc Arnd, Rob] On Thu, Aug 25, 2022 at 08:27:52PM +0800, Yang Yingliang wrote: > If device_register() fails in pci_register_host_bridge(), the refcount > of bus device is leaked, so device name that set by dev_set_name() can > not be freed. Fix this by calling put_device() when device_register() > fails, so the device name will be freed in kobject_cleanup(). > > Fixes: 37d6a0a6f470 ("PCI: Add pci_register_host_bridge() interface") > Signed-off-by: Yang Yingliang > --- > drivers/pci/probe.c | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index e500eb9d6468..292d9da146ce 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -948,8 +948,17 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) > name = dev_name(&bus->dev); > > err = device_register(&bus->dev); > - if (err) > - goto unregister; > + if (err) { > + /* > + * release_pcibus_dev() will decrease the refcount of bridge > + * device and free the memory of bus. > + * The memory of bus device name will be freed when the refcount > + * get to zero. > + */ > + put_device(&bus->dev); > + device_unregister(&bridge->dev); > + return err; > + } Calling put_device(X) after device_register(X) returns failure doesn't need explanation because that's the standard pattern. I think that was just missing before. In this error case, we previously did called put_device() for the *bridge* instead of the bus. That was likely a typo and seems like the important thing here. > pcibios_add_bus(bus); > > @@ -1025,10 +1034,6 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) > > return 0; > > -unregister: > - put_device(&bridge->dev); > - device_unregister(&bridge->dev); > - > free: > kfree(bus); > return err; > -- > 2.25.1 >