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=-2.8 required=3.0 tests=BAYES_00,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 7E75CC433DB for ; Thu, 11 Mar 2021 23:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53BF864F76 for ; Thu, 11 Mar 2021 23:13:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230508AbhCKXNZ (ORCPT ); Thu, 11 Mar 2021 18:13:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229796AbhCKXNN (ORCPT ); Thu, 11 Mar 2021 18:13:13 -0500 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F0DFC061574; Thu, 11 Mar 2021 15:13:12 -0800 (PST) Received: by mail-pj1-x1036.google.com with SMTP id j6-20020a17090adc86b02900cbfe6f2c96so10126349pjv.1; Thu, 11 Mar 2021 15:13:12 -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=bU9j8QS9UEqtU91hrNDexuTDXigIeltrQEJrDXB39JU=; b=f/kuHReiRdBMXdOa966VBks+JO5X0AAmZaiPPeBGrQwvKqvQ+CoD8qjV0uQPREWRWw kadZC5M5uY7DFdui29GRMfDwEtxCy3Wbx118+IUwqSe+lPsb54h4N0OYNNB9yyxg00oa L0KycMqH4/jDv7S43dH6PV3jHzLfhkS7HX0mScTYZ2tZUpAL0oiSv9xzVWPDelvLGrBE Perdg5mKo4+BR34Hk3I/luPCkFHgGSD7Qpn4cChs+DVRKr9k2sAXmNndgBhMMKHk7MS6 MQkYlftREEuPfE9Zt8D2QQbjv0u8QpWSfRODvd0owNP62OcuPwIrGZDIC5QOlYlnEO6m wDZA== 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=bU9j8QS9UEqtU91hrNDexuTDXigIeltrQEJrDXB39JU=; b=DMYkSsNfWYXyvhCkVCIAlEwG4EkQrGDcMNaa0sDR8zcZK9KV7OSD3x7g3CmJu4tw2U 6Kb4R6irrPHJNWp2qv0pfuQJtNN/jd51U6tM7XXqLkYiNH3Ke2Fz0klvkSOV0JgnF+/a jmRVke46c/DsESNJUisf4kFGnstZdqgAEfxFMAdzoUUHchAHziPYptHUpqO8D7DhHJqL aVOBMvcUhRYVKXtOjcnvo7zdcHbF5SPRUIwcsl/dsnPT2SvI2w7FP7T6WSJpC0NnUgtb 8a1kTG4Hw/ZDZYACwwy2JCxIRL8AxMG6Nsb2TOw/oqE6naUJY5G6eH6aahPinr45e0fN pS7g== X-Gm-Message-State: AOAM531pYXUwBLdbYPRUCNzWAXiUDixXcZQq4VP20ew+xN74jqOmW/Yx cxnnB0SjPcZawKRlmdHLmWy7KEoXSxEeVPnvPSTbj6n5vTI= X-Google-Smtp-Source: ABdhPJxCQlZY7oDGdfCTApTySwUAzoKFFF1LkwbBouxB3bZObIYRGghCCCfAIky1XLTOTgoYXqyOfWvpPJVug9y+5Xs= X-Received: by 2002:a17:90a:ea91:: with SMTP id h17mr11119542pjz.66.1615504392023; Thu, 11 Mar 2021 15:13:12 -0800 (PST) MIME-Version: 1.0 References: <20210311072311.2969-1-xie.he.0141@gmail.com> <20210311124309.5ee0ef02@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210311145230.5f368151@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210311145230.5f368151@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Xie He Date: Thu, 11 Mar 2021 15:13:01 -0800 Message-ID: Subject: Re: [PATCH net] net: lapbether: Prevent racing when checking whether the netif is running To: Jakub Kicinski Cc: Martin Schiller , "David S. Miller" , Linux X25 , Linux Kernel Network Developers , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 11, 2021 at 2:52 PM Jakub Kicinski wrote: > > Normally driver's ndo_stop() calls netif_tx_disable() which takes TX > locks, so unless your driver is lockless (LLTX) there should be no xmit > calls after that point. Do you mean I should call "netif_tx_disable" inside my "ndo_stop" function as a fix for the racing between "ndo_stop" and "ndo_start_xmit"? I can't call "netif_tx_disable" inside my "ndo_stop" function because "netif_tx_disable" will call "netif_tx_stop_queue", which causes another racing problem. Please see my recent commit f7d9d4854519 ("net: lapbether: Remove netif_start_queue / netif_stop_queue")