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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 76CD9C432C0 for ; Fri, 29 Nov 2019 05:54:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3DF21215F1 for ; Fri, 29 Nov 2019 05:54:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="drRBrsLJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726821AbfK2Fyz (ORCPT ); Fri, 29 Nov 2019 00:54:55 -0500 Received: from mail-io1-f65.google.com ([209.85.166.65]:37091 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726164AbfK2Fyy (ORCPT ); Fri, 29 Nov 2019 00:54:54 -0500 Received: by mail-io1-f65.google.com with SMTP id k24so20511450ioc.4; Thu, 28 Nov 2019 21:54:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jmqoLt1Ipq80GEdpA7uVx5mVDtS/SHGillzYT51kWkE=; b=drRBrsLJwOsSDbcgTdjYnL5YhMtimm45cqMj6s4jIv1ZiQMoJ+n2QJ7Y4N2fpxng+k Av+QFRIqa3MGfDJvB6fXNrrtHwh/kKJkEwpY9NxTP5WdivkgkRF61Ef6lL7lkGNhzDUn mBh9Eabz7V+PMQcprEOS3wCgTBqMtOwzW53Da7vf+dbdon4HexOvCTcVAdFWAV/fyDQQ KvrRpmTc4IPAcG2Rmqyz5DUUXcMHWsyn6PctBCfMdcRQtValX9jxUzw/OogRD1nIfNKC zghJpMGqLmvnXVts6NHiYcNaN/WiKBs/svtV0BjUNRC61e+3CXOCi/kv/X5GG9ScEWIR Wlww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jmqoLt1Ipq80GEdpA7uVx5mVDtS/SHGillzYT51kWkE=; b=XdJU8TheBbhTC+up6Wx+DJOmJgBlo32F3IPJ3Jgaiq9PqdxKwBlUbYNdCUdyxKiZdq bU+Rmg18OhpttAc91ViAheUjsFePQxBiRJcPY5Nmq/++aeOdUThqILzps7YATSnYsUeS 8V+c7HRA+zmgvyVv0louhi3/1l7HPzE/gqZauhPifxUFCf/7eRLCt7mB3HCZyvmW2eT0 kc10p3y8+UXkVC2BwszKfqOaaXPuEjVj+OKY/u1oXLNiG19uVfx+hsNIcNN/s2aaMLCP jk0dh3W+vNUZ/Kt6dzr/vdVcplg+FmDs0MGqCNvqUhQK06WSgpO5iA6ucSxBpVzETqRx gZ6w== X-Gm-Message-State: APjAAAVJCs9ifF4MWHI0cvs6P+gRJydiISXO03DjK/x6AG6bcZ3qMCTt KRUlPRljM4cwcSuOM8+nExsg7TbsmzbiWfIwZ3E= X-Google-Smtp-Source: APXvYqwV3CFFzruKf9Fkvty9F4uglgcC+7qYiLkkXVZIkvaTCtnY+i383rzfNHnGK2g/uDxWCVCXSbrggK+AdFMZcrU= X-Received: by 2002:a02:a08:: with SMTP id 8mr8538761jaw.98.1575006893958; Thu, 28 Nov 2019 21:54:53 -0800 (PST) MIME-Version: 1.0 References: <0000000000007d22100573d66078@google.com> In-Reply-To: From: Lukas Bulwahn Date: Fri, 29 Nov 2019 06:54:47 +0100 Message-ID: Subject: Re: unregister_netdevice: waiting for DEV to become free (2) To: Tetsuo Handa Cc: syzbot , YueHaibing , Jouni Hogander , Julian Anastasov , ddstreet@ieee.org, Dmitry Vyukov , Linux Kernel Mailing List , Netdev , syzkaller-bugs@googlegroups.com, Hulk Robot , "David S. Miller" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 28, 2019 at 10:56 AM Tetsuo Handa wrote: > > Hello people involved in commit a3e23f719f5c4a38 ("net-sysfs: call dev_hold if kobject_init_and_add success") > and commit b8eb718348b8fb30 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject"). > > syzbot is reporting that unregister_netdevice() hangs due to underflowing > device refcount when kobject_init_and_add() failed due to -ENOMEM. > Tetsuo, would you happen to have a C reproducer program that creates the trace you reported? I could not quickly find one that by the date would fit to when we included our change on this syzbot page: https://syzkaller.appspot.com/bug?id=bae9a2236bfede42cf3d219e6bf6740c583568a4 Jouni, can you please follow up on this report. Thanks. Lukas