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 95AC3C33C99 for ; Tue, 7 Jan 2020 05:36:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D3042070E for ; Tue, 7 Jan 2020 05:36:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Z7rTzJfv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725920AbgAGFgc (ORCPT ); Tue, 7 Jan 2020 00:36:32 -0500 Received: from mail-ot1-f50.google.com ([209.85.210.50]:46680 "EHLO mail-ot1-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725267AbgAGFgc (ORCPT ); Tue, 7 Jan 2020 00:36:32 -0500 Received: by mail-ot1-f50.google.com with SMTP id r9so1521480otp.13 for ; Mon, 06 Jan 2020 21:36:31 -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=g4G2+9KohDaOObSuO5Pc+lXm4AZk8YwByEWZoUANwxQ=; b=Z7rTzJfvdK7dCntaSmKfJjkfsN49nq8CUHqBFFMGnIxurFpvDDIBhpPwHAUTxu9BWv HPCTq3ZiVJzHDMZT+uL/699tUZK5mJEtWpFuyIJxhTADrk7HtEFN9EWuEAnXQgsTvkrk uWq2LeKEceAlj7DbmVX2SyVJ+xxyBl9wIvosRamnOdEHuu8DqWB/9nC0w+ASG6JmOcpl 508jkxGv71wIk/xqOl/8ZslycUrobTTu0t6V25+g5QtWqIOaHhT2Kix2LJRUNegHQTgm Tp9EuxcG+aU9W1GmK0y3pt8nQ6FpqzK+X/0jiVJUgFTChEL4Z8bKev0OYqg+961u0T82 vomA== 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=g4G2+9KohDaOObSuO5Pc+lXm4AZk8YwByEWZoUANwxQ=; b=Hffv05mDOSXOKlZZ0gm8Rsm9ddrc66eqoSfRfzscD0GyVDI3HDAo8OCURPyQcfApbv jEPgzkv2Fq+faAZ73KBSkFiAnFjHsHN8F/Eck60AKi2tXsFf8GkQ3o9SbpX/6rV+GVLQ f8YUS3SsmeleoHPgvEP+/VnfHYhPfTMAwjeAon+uDDn0CYgsjhWEyRKZgCn5P0XFar9O ZNeHiePldppQ4UrI1mLwhrB8Sk+0v8ijpetq/y7q0cN4LblEft0dcme3UBugEwuPwx9I Q18DRoiHwtd7+4XmPXMPwRs3y7jCTRy8/HZlBiv28A7p9DHIZhMG1OI3DXY4nFqQ0GDN znLA== X-Gm-Message-State: APjAAAUYEUtiWwQ6hlfkAuaSWNajmUELx0XSsc/M/wh0hTm1i814dljc JpOyMdPs9V434P/Wsyp3lADrKKAi3uVYADy9of4= X-Google-Smtp-Source: APXvYqxjd194P2jcATC2gFY4q+3SdDY/bUNdPLajogCf6QTeXkpesgZHyi32DsGKwV+YTQoUdJxpgWnO2+FGfAnLKoo= X-Received: by 2002:a9d:62c7:: with SMTP id z7mr110171752otk.189.1578375391425; Mon, 06 Jan 2020 21:36:31 -0800 (PST) MIME-Version: 1.0 References: <000000000000ab3f800598cec624@google.com> <000000000000802598059b6c7989@google.com> In-Reply-To: <000000000000802598059b6c7989@google.com> From: Cong Wang Date: Mon, 6 Jan 2020 21:36:20 -0800 Message-ID: Subject: Re: WARNING: bad unlock balance in sch_direct_xmit To: syzbot Cc: Taehee Yoo , Linux Kernel Network Developers Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, Taehee On Sun, Jan 5, 2020 at 2:59 PM syzbot wrote: > > syzbot has bisected this bug to: > > commit ab92d68fc22f9afab480153bd82a20f6e2533769 > Author: Taehee Yoo > Date: Mon Oct 21 18:47:51 2019 +0000 > > net: core: add generic lockdep keys Why netdev_update_lockdep_key() is needed? It causes the bug here because the unregister and register are not atomic although under RTNL, fast path could still lock with one key and unlock with another key after the previous got unregistered. >From my understand of lockdep here, as long as the device itself is not changed, it doesn't need to update those keys. Thanks.