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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF155C432C0 for ; Wed, 20 Nov 2019 06:59:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8CE3222A2 for ; Wed, 20 Nov 2019 06:59:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=unikie-com.20150623.gappssmtp.com header.i=@unikie-com.20150623.gappssmtp.com header.b="02R2RaYC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727615AbfKTG7b (ORCPT ); Wed, 20 Nov 2019 01:59:31 -0500 Received: from mail-lj1-f193.google.com ([209.85.208.193]:35310 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725268AbfKTG7a (ORCPT ); Wed, 20 Nov 2019 01:59:30 -0500 Received: by mail-lj1-f193.google.com with SMTP id r7so26234933ljg.2 for ; Tue, 19 Nov 2019 22:59:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=unikie-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:references:date:in-reply-to:message-id :user-agent:mime-version:content-transfer-encoding; bh=EtYzPJ3xgyfV8PEix2L28b58r2Oi7XfTDsfJqJbKR+g=; b=02R2RaYCsWHDix1OmMUyIv+Sdb1ZJ38A77A0gM6YdcxAbkv1sPeYhvPfEzi3k/xDDl UOenCtIIZF9y0MCZkaV59ySka82WyR77okJTpislcFTlsWHgnqHp2zdm3CIDNzrbOq/i ZLG8uiNw9Ffbv+qMkmv//n1LRRMt+c1j5Sdjp4g1kUoa7LTgYJZclP+ME4oqV30r1AJJ O6fHTgBrkpp3WkAMPht7LSBQo1w64Ul+CpRHZTB72OagtFz0YRkTkomRInbI3/8FLhu0 RTBx2VUd6qp1G6EX7hmTTGbLdPkOlRTcaRvYVzSeIOh8R1SwupXOvFDio2PZlCzKvEIl Jw1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:references:date:in-reply-to :message-id:user-agent:mime-version:content-transfer-encoding; bh=EtYzPJ3xgyfV8PEix2L28b58r2Oi7XfTDsfJqJbKR+g=; b=o9A77Q0vswOLMqSV3f3tdkOgoMNImTeudW9zLvPFBUXx/QdI6F3qhTPH/7v+ynPB0x dNA7iLBX7UCHgrBaEtnBtDV6Ens/h74gNrbM92tbEsKuIMTGV3IBLbabNppXjHPpPCl2 jLV/6pD4Nospw5sKjfURW4PEw3qXtvpJMEEnZaKq1FKOz/pubAosHbs2oplbDPyrz4wO 9H8YuzT4TfrX03LXIfLYp/NOaNAZYsQc/kQwrhSddh50v/zOghPzNYQ8PnaA3u2vMBYe nDP7o72lWDg3iCcln3Ujp3QLSQHQf3eM3ub1NrM1Egc++Nhq+p7VSg28NETIQJkngoG7 pvqg== X-Gm-Message-State: APjAAAVBtQHGoCtEjS3OPB5Y19QMkIiZyYttmTYfBF7Abs4B5667KLF9 RuwD3zaPX3pjny3l4YjkS9lhfbpl70A= X-Google-Smtp-Source: APXvYqxUTZfbQxAYmN7JlS+nvet/9h+Ckwg5xjmqWiLGSjlJLucbq5CuP9q90UuxfN0fe0oRSAMRaQ== X-Received: by 2002:a2e:547:: with SMTP id 68mr1229505ljf.150.1574233168414; Tue, 19 Nov 2019 22:59:28 -0800 (PST) Received: from GL-434 ([109.204.235.119]) by smtp.gmail.com with ESMTPSA id m9sm3449524lfj.54.2019.11.19.22.59.27 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 19 Nov 2019 22:59:27 -0800 (PST) From: jouni.hogander@unikie.com (Jouni =?utf-8?Q?H=C3=B6gander?=) To: David Miller Cc: netdev@vger.kernel.org, lukas.bulwahn@gmail.com Subject: Re: [PATCH] net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject References: <20191119095121.6295-1-jouni.hogander@unikie.com> <20191119.171333.624799505921966746.davem@davemloft.net> Date: Wed, 20 Nov 2019 08:59:26 +0200 In-Reply-To: <20191119.171333.624799505921966746.davem@davemloft.net> (David Miller's message of "Tue, 19 Nov 2019 17:13:33 -0800 (PST)") Message-ID: <87wobvqbht.fsf@unikie.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org David Miller writes: > From: jouni.hogander@unikie.com > Date: Tue, 19 Nov 2019 11:51:21 +0200 > >> kobject_init_and_add takes reference even when it fails. > > I see this in the comment above kobject_init_and_add() but not in the > code. > > Where does the implementation of kobject_init_and_add() actually take > such a reference? kobject_init_and_add -> kobject_init -> kobject_init_internal -> kref_init kref_init initializes ref_count as 1. > > Did you discover this by code inspection, or by an actual bug that was > triggered? If by an actual bug, please provide the OOPS and/or checker > trace that indicated a leak was happening here. Originally found it via memory leak identified by Syzkaller. I will submit new one with memleak dump. > > I don't see anything actually wrong here because kobject_init_and_add() > doesn't actually seem to do what it's comment suggests... See the code path above. BR, Jouni H=C3=B6gander