From patchwork Mon Mar 29 19:25:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 411174 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 C9001C433DB for ; Mon, 29 Mar 2021 19:26:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8DF3F6196E for ; Mon, 29 Mar 2021 19:26:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231151AbhC2TZo (ORCPT ); Mon, 29 Mar 2021 15:25:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230213AbhC2TZ0 (ORCPT ); Mon, 29 Mar 2021 15:25:26 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 716CDC061574 for ; Mon, 29 Mar 2021 12:25:26 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id f17so4887879plr.0 for ; Mon, 29 Mar 2021 12:25:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=tO8m3MHXqx64GGnYKe37wp1RmF5biVoA87KhNwuEcpI=; b=cHEPmwA8YsF6jxftS+4ZVTTZpH8GLFm7T3TTowc2jIkg1cVxgB6pA2PdZwbtRm5mTd xF8BKv4mPDy1V6SpoOaPPrjRuSliw6esd40G7Fu+rKWblumwviHZ7v0xAcZigOUJ1hG8 jd3znYl1lORcn/D3QJxVp5x/cGZUBQHA1pEBzAT3puoljoN0Bwuz1RtXa/a5QPq9nYhg Vyq9trYYJEWCoAd+zOYhk8HMZ1hUQd62BoHqpt3+J+R4mTj9Hu2jN5ziit2Gco2mbyn6 hRWnmBxPXnfqxHrh8bWWf/ghJH46HqNbhhGUjaHP2vEJU2wc2ymelHcLEpCRvoDthUxB jCwA== 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:date:message-id:mime-version :content-transfer-encoding; bh=tO8m3MHXqx64GGnYKe37wp1RmF5biVoA87KhNwuEcpI=; b=W5P4pi4JBJf+ujvP/1ryGU7L1sTVYXj4tqsN0JrK3O4pTPooJ79QUK4A6ztJF8yYYs 5WYMojkCgFn2vdF+8LMHZtNqQbd2z7/lIlN/64ogeBpHa9EEb7kxXBwHFPoiAPsrfc6S JroeBJkKvGc5eka6EMUWo+KLONRG5Mp9ro1bYeWHXs1jLI2oL92PfVAg5eY/4Fw6F99X esk2fjUFFc+qN+sBAbLAdeDADLrhc11M2TKjkpYUsL+jPBKMBV4gc6MHhAByEp59gQ0B HxJ3mORqYMfu9fxyvKptjyEEQY0/bBjFM0oTAbWqRjsvKxElGIsBR9MzGpElag1izdec 7T2Q== X-Gm-Message-State: AOAM533u2kKmx4iupW7/P2PrHBfpkhv/rGclPpCgoLyDtyxvlBa+VsnU VHJBwxlOvMHF0swpQQUZAAG0aHVQcKA= X-Google-Smtp-Source: ABdhPJwlDiLqdvlFAewZk7AXlht6RTNwRElenB/TnUrtKzLWYewNyWA1jJfsQal0mDItxWdvQEEY2g== X-Received: by 2002:a17:902:7888:b029:e6:b94d:c72 with SMTP id q8-20020a1709027888b02900e6b94d0c72mr31276242pll.8.1617045925981; Mon, 29 Mar 2021 12:25:25 -0700 (PDT) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:78a0:7565:129d:828c]) by smtp.gmail.com with ESMTPSA id w23sm10825464pgi.63.2021.03.29.12.25.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Mar 2021 12:25:25 -0700 (PDT) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski Cc: netdev , Eric Dumazet , Eric Dumazet , syzbot Subject: [PATCH net-next] sit: proper dev_{hold|put} in ndo_[un]init methods Date: Mon, 29 Mar 2021 12:25:22 -0700 Message-Id: <20210329192522.155336-1-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger a warning [1] Issue here is that: - all dev_put() should be paired with a corresponding prior dev_hold(). - A driver doing a dev_put() in its ndo_uninit() MUST also do a dev_hold() in its ndo_init(), only when ndo_init() is returning 0. Otherwise, register_netdevice() would call ndo_uninit() in its error path and release a refcount too soon. Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT") Signed-off-by: Eric Dumazet Reported-by: syzbot --- net/ipv6/sit.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index b9bd2723f89a314d15c8c4ea785e84530c8acb95..488d3181aec3a5558dbefb6145400627535df761 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -218,8 +218,6 @@ static int ipip6_tunnel_create(struct net_device *dev) ipip6_tunnel_clone_6rd(dev, sitn); - dev_hold(dev); - ipip6_tunnel_link(sitn, t); return 0; @@ -1456,7 +1454,7 @@ static int ipip6_tunnel_init(struct net_device *dev) dev->tstats = NULL; return err; } - + dev_hold(dev); return 0; }