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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 8E43DC433B4 for ; Thu, 20 May 2021 09:27:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74D3B6139A for ; Thu, 20 May 2021 09:27:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232270AbhETJ2m (ORCPT ); Thu, 20 May 2021 05:28:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:54734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231549AbhETJ1e (ORCPT ); Thu, 20 May 2021 05:27:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C40FD61363; Thu, 20 May 2021 09:26:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621502773; bh=p/ygo+1Wb6+E/Plt2HTQEAWZfAZPL1UudxQB/9P9TS4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z+gO4BgOG+0/X8iU7OR6CMJgI3p60IVk/dJ8SY4uQ7/ii5YRHlgFFU6B8RCMHokGu mab7eza0Gle7bCjMZ5puaujW89ezD66lRt7wNwWOygbVnI5tCTfkOSdeHpeddX8oqX D+Gs0fCKXN8FoqIOyv6F0EY86QPKrb7VWHlo2ExU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , "David S. Miller" Subject: [PATCH 5.12 43/45] sit: proper dev_{hold|put} in ndo_[un]init methods Date: Thu, 20 May 2021 11:22:31 +0200 Message-Id: <20210520092054.909014767@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092053.516042993@linuxfoundation.org> References: <20210520092053.516042993@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet commit 6289a98f0817a4a457750d6345e754838eae9439 upstream. 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/sit.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -218,8 +218,6 @@ static int ipip6_tunnel_create(struct ne 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_ dev->tstats = NULL; return err; } - + dev_hold(dev); return 0; }