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=-11.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 B474AC4727E for ; Wed, 23 Sep 2020 19:59:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7300E2371F for ; Wed, 23 Sep 2020 19:59:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="o84bTiU0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726600AbgIWT7L (ORCPT ); Wed, 23 Sep 2020 15:59:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726199AbgIWT7K (ORCPT ); Wed, 23 Sep 2020 15:59:10 -0400 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C673C0613CE; Wed, 23 Sep 2020 12:59:10 -0700 (PDT) Received: by mail-wr1-x441.google.com with SMTP id x14so1275926wrl.12; Wed, 23 Sep 2020 12:59:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=wmckwTRXRvwQPVN9iH8EtFcdLmuwcKJsSJQfHvWc6QA=; b=o84bTiU0vqCk8XXCH5L4VxLBL1T+vJsaC4axNiyRlTtxnhGFoJ6Zn6OW9PJpWWkVMM /7KCWAkro1wKfRJtBI9RuTvp1vjAJ9v3Ov1/DZTqhlqaJa4l2OXpXy2B/zTwcYHalCGb ACCiOmXDpXRZEbpdWtjJxtfHLYP0mCg/FJRlFvbG4zLKJCKqbX8JSY3G38ZVQ4KchUNw KfYuwgMb1G7yd4Rp0q1KjPjD3LWn/jz7MYZbmx9FPwDiCISI1aPceUn0XbBr/yMwXnLK TgihhXGO8OX/KUDlspz4F8n5aobr2BbGgCf+IgaM2kwTLYza1CJoOcclOLcLUlvD7d8L MEGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=wmckwTRXRvwQPVN9iH8EtFcdLmuwcKJsSJQfHvWc6QA=; b=oIqQsVmrYxPWRLvsfLkTaMKeQqNcoaHIeiMzitp9WzqneGDKjCksGJX8keQzgSRSb5 1U+mJOLR3e+eE4ot8iyq123+SQ5bwTaVLtKEaQVQujbvmmBI2lADO50Y/ffndPeCuvu+ NRyigNKgZYhYXmB5+cNDq9Q+iyDKxBbzI84afH6pILxsS5rs2N5QiAxicrql2FbHoRq8 uZyI6tlmHgZRouPEqnPm9qTwscN6PrTCgqQhyKzWYVRmZLS/823tFTNqLDbpcQ9TsmL2 K+GuM2RsUXqXWex+rO02R3/PPKj/xJhRkeV2Ea4YuMc585j7CSSuJXK8honuDNVL4FvL uZQg== X-Gm-Message-State: AOAM532W5Ave3/IwtHCnz5RwVoGAQ/O4WzklrgXkQ0iaSP32OMt9zr0U ctsTFLFQrwzoZuNQP6Wj5vTMuh6RgWU= X-Google-Smtp-Source: ABdhPJy2z/Hrts/zKxyRH/xTHeWNyCPxMQZw5ecoJ/QD4Prcgxb8eBJLN8/cP/vkQSC9Z3I6ycjNAw== X-Received: by 2002:adf:fa52:: with SMTP id y18mr1339142wrr.264.1600891147751; Wed, 23 Sep 2020 12:59:07 -0700 (PDT) Received: from ?IPv6:2003:ea:8f23:5700:9dd1:2d79:8cda:7fd2? (p200300ea8f2357009dd12d798cda7fd2.dip0.t-ipconnect.de. [2003:ea:8f23:5700:9dd1:2d79:8cda:7fd2]) by smtp.googlemail.com with ESMTPSA id v17sm1044439wrc.23.2020.09.23.12.59.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 23 Sep 2020 12:59:07 -0700 (PDT) Subject: Re: [PATCH] Revert "net: linkwatch: add check for netdevice being present to linkwatch_do_dev" To: Saeed Mahameed , Geert Uytterhoeven , Florian Fainelli , Andrew Lunn , "David S . Miller" , Jakub Kicinski Cc: Gaku Inami , Yoshihiro Shimoda , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200901150237.15302-1-geert+renesas@glider.be> <7bfebfdc0d7345c4612124ff00e20eebb0ff6cd9.camel@kernel.org> <3d9176a6-c93e-481c-5877-786f5e6aaef8@gmail.com> <28da797abe486e783547c60a25db44be0c030d86.camel@kernel.org> From: Heiner Kallweit Message-ID: <14f41724-ce45-c2c0-a49c-1e379dba0cb5@gmail.com> Date: Wed, 23 Sep 2020 21:58:59 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <28da797abe486e783547c60a25db44be0c030d86.camel@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 23.09.2020 20:35, Saeed Mahameed wrote: > On Wed, 2020-09-23 at 13:49 +0200, Heiner Kallweit wrote: >> On 18.09.2020 19:58, Saeed Mahameed wrote: >>> On Tue, 2020-09-01 at 17:02 +0200, Geert Uytterhoeven wrote: >>>> This reverts commit 124eee3f6955f7aa19b9e6ff5c9b6d37cb3d1e2c. >>>> >>>> Inami-san reported that this commit breaks bridge support in a >>>> Xen >>>> environment, and that reverting it fixes this. >>>> >>>> During system resume, bridge ports are no longer enabled, as that >>>> relies >>>> on the receipt of the NETDEV_CHANGE notification. This >>>> notification >>>> is >>>> not sent, as netdev_state_change() is no longer called. >>>> >>>> Note that the condition this commit intended to fix never existed >>>> upstream, as the patch triggering it and referenced in the commit >>>> was >>>> never applied upstream. Hence I can confirm s2ram on >>>> r8a73a4/ape6evm >>>> and sh73a0/kzm9g works fine before/after this revert. >>>> >>>> Reported-by Gaku Inami >>>> Signed-off-by: Geert Uytterhoeven >>>> --- >>>> net/core/link_watch.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/net/core/link_watch.c b/net/core/link_watch.c >>>> index 75431ca9300fb9c4..c24574493ecf95e6 100644 >>>> --- a/net/core/link_watch.c >>>> +++ b/net/core/link_watch.c >>>> @@ -158,7 +158,7 @@ static void linkwatch_do_dev(struct >>>> net_device >>>> *dev) >>>> clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); >>>> >>>> rfc2863_policy(dev); >>>> - if (dev->flags & IFF_UP && netif_device_present(dev)) { >>>> + if (dev->flags & IFF_UP) { >>> >>> So with your issue the devices is both IFF_UP and !present ? how so >>> ? >>> I think you should look into that. >>> >>> I am ok with removing the "dev present" check from here just >>> because we >>> shouldn't be expecting IFF_UP && !present .. such thing must be a >>> bug >>> somewhere else. >>> >>>> if (netif_carrier_ok(dev)) >>>> dev_activate(dev); >>>> else >> >> In __dev_close_many() we call ndo_stop() whilst IFF_UP is still set. >> ndo_stop() may detach the device and bring down the PHY, resulting in >> an > > Why would a driver detach the device on ndo_stop() ? > seems like this is the bug you need to be chasing .. > which driver is doing this ? > Some drivers set the device to PCI D3hot at the end of ndo_stop() to save power (using e.g. Runtime PM). Marking the device as detached makes clear to to the net core that the device isn't accessible any longer. >> async link change event that calls dev_get_stats(). The latter call >> may >> have a problem if the device is detached. In a first place I'd >> consider >> such a case a network driver bug (ndo_get_stats/64 should check for >> device presence if depending on it). > > Device drivers should avoid presence check as much as possible > especially in ndo, this check must be performed by the stack. > That's a question I also stumbled across. For the ethtool ops dev_ethtool() checks whether device is present. But for ndo that's not always the case, e.g. dev_get_stats() doesn't check for device presence before calling ndo_get_stats() or ndo_get_stats64(). To a certain extent I can understand this behavior, because drivers may just use internal data structures in ndo ops instead of accessing the device. >> The additional check in linkwatch_do_dev() was meant to protect from >> such >> driver issues. >