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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 ED836C0650E for ; Wed, 3 Jul 2019 18:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C576121881 for ; Wed, 3 Jul 2019 18:25:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727095AbfGCSZD (ORCPT ); Wed, 3 Jul 2019 14:25:03 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:60448 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725933AbfGCSZC (ORCPT ); Wed, 3 Jul 2019 14:25:02 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 1EC32140CFF56; Wed, 3 Jul 2019 11:25:02 -0700 (PDT) Date: Wed, 03 Jul 2019 11:24:59 -0700 (PDT) Message-Id: <20190703.112459.875695376158111859.davem@davemloft.net> To: maheshb@google.com Cc: netdev@vger.kernel.org, edumazet@google.com, mahesh@bandewar.net, geert@linux-m68k.org Subject: Re: [PATCH next] loopback: fix lockdep splat From: David Miller In-Reply-To: <20190703061631.84485-1-maheshb@google.com> References: <20190703061631.84485-1-maheshb@google.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 03 Jul 2019 11:25:02 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Mahesh Bandewar Date: Tue, 2 Jul 2019 23:16:31 -0700 > dev_init_scheduler() and dev_activate() expect the caller to > hold RTNL. Since we don't want blackhole device to be initialized > per ns, we are initializing at init. > > [ 3.855027] Call Trace: > [ 3.855034] dump_stack+0x67/0x95 > [ 3.855037] lockdep_rcu_suspicious+0xd5/0x110 > [ 3.855044] dev_init_scheduler+0xe3/0x120 > [ 3.855048] ? net_olddevs_init+0x60/0x60 > [ 3.855050] blackhole_netdev_init+0x45/0x6e > [ 3.855052] do_one_initcall+0x6c/0x2fa > [ 3.855058] ? rcu_read_lock_sched_held+0x8c/0xa0 > [ 3.855066] kernel_init_freeable+0x1e5/0x288 > [ 3.855071] ? rest_init+0x260/0x260 > [ 3.855074] kernel_init+0xf/0x180 > [ 3.855076] ? rest_init+0x260/0x260 > [ 3.855078] ret_from_fork+0x24/0x30 > > Fixes: 4de83b88c66 ("loopback: create blackhole net device similar to loopack.") > Reported-by: Geert Uytterhoeven > Cc: Eric Dumazet > Signed-off-by: Mahesh Bandewar Applied.