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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 390F6C56201 for ; Mon, 9 Nov 2020 13:15:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C80362083B for ; Mon, 9 Nov 2020 13:15:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927754; bh=WwrdyJ6rev8UyFlG0RTKTPWToaElwvLFV3wOtR5Dg1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=G2qSzSi+M2NXnnIFMg2fD6X7xtorQpKvGNonapz7MOQh4ThEXbP42kbeHQ+YRSP7f 2HyOPwCg51jvdL0DYohw/Owa7rVIEEXG4QsjT2FtqQnQqiueunQYCoD5n5mzKVzQfj sbT39XeORlh6Iok/AE7o5zc32EfFV26epxdZ6p0U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733311AbgKINPx (ORCPT ); Mon, 9 Nov 2020 08:15:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:42692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732711AbgKINPt (ORCPT ); Mon, 9 Nov 2020 08:15:49 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BFB4120867; Mon, 9 Nov 2020 13:15:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927749; bh=WwrdyJ6rev8UyFlG0RTKTPWToaElwvLFV3wOtR5Dg1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LqSLP1/tLFMrsF6oVXziQzs82nDmDI77C5NpyHGn3i2xXiCUEVRk6lRBFn45FV6Q/ gZDk8B5Ru0zUTZMrtKB8we9PK6vkD3MtfGdmUi7cgrx4CLYErDNmtvmTBhOOz9P6Sh 8d+Fxf9Y4QhDbhFvl4RGOGzqB6oetyhbyNDLXfV4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+4a0f7bc34e3997a6c7df@syzkaller.appspotmail.com, Taehee Yoo , Jakub Kicinski Subject: [PATCH 5.9 001/133] net: core: use list_del_init() instead of list_del() in netdev_run_todo() Date: Mon, 9 Nov 2020 13:54:23 +0100 Message-Id: <20201109125030.785403629@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125030.706496283@linuxfoundation.org> References: <20201109125030.706496283@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore 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: Taehee Yoo commit 0e8b8d6a2d85344d80dda5beadd98f5f86e8d3d3 upstream. dev->unlink_list is reused unless dev is deleted. So, list_del() should not be used. Due to using list_del(), dev->unlink_list can't be reused so that dev->nested_level update logic doesn't work. In order to fix this bug, list_del_init() should be used instead of list_del(). Test commands: ip link add bond0 type bond ip link add bond1 type bond ip link set bond0 master bond1 ip link set bond0 nomaster ip link set bond1 master bond0 ip link set bond1 nomaster Splat looks like: [ 255.750458][ T1030] ============================================ [ 255.751967][ T1030] WARNING: possible recursive locking detected [ 255.753435][ T1030] 5.9.0-rc8+ #772 Not tainted [ 255.754553][ T1030] -------------------------------------------- [ 255.756047][ T1030] ip/1030 is trying to acquire lock: [ 255.757304][ T1030] ffff88811782a280 (&dev_addr_list_lock_key/1){+...}-{2:2}, at: dev_mc_sync_multiple+0xc2/0x150 [ 255.760056][ T1030] [ 255.760056][ T1030] but task is already holding lock: [ 255.761862][ T1030] ffff88811130a280 (&dev_addr_list_lock_key/1){+...}-{2:2}, at: bond_enslave+0x3d4d/0x43e0 [bonding] [ 255.764581][ T1030] [ 255.764581][ T1030] other info that might help us debug this: [ 255.766645][ T1030] Possible unsafe locking scenario: [ 255.766645][ T1030] [ 255.768566][ T1030] CPU0 [ 255.769415][ T1030] ---- [ 255.770259][ T1030] lock(&dev_addr_list_lock_key/1); [ 255.771629][ T1030] lock(&dev_addr_list_lock_key/1); [ 255.772994][ T1030] [ 255.772994][ T1030] *** DEADLOCK *** [ 255.772994][ T1030] [ 255.775091][ T1030] May be due to missing lock nesting notation [ 255.775091][ T1030] [ 255.777182][ T1030] 2 locks held by ip/1030: [ 255.778299][ T1030] #0: ffffffffb1f63250 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x2e4/0x8b0 [ 255.780600][ T1030] #1: ffff88811130a280 (&dev_addr_list_lock_key/1){+...}-{2:2}, at: bond_enslave+0x3d4d/0x43e0 [bonding] [ 255.783411][ T1030] [ 255.783411][ T1030] stack backtrace: [ 255.784874][ T1030] CPU: 7 PID: 1030 Comm: ip Not tainted 5.9.0-rc8+ #772 [ 255.786595][ T1030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 255.789030][ T1030] Call Trace: [ 255.789850][ T1030] dump_stack+0x99/0xd0 [ 255.790882][ T1030] __lock_acquire.cold.71+0x166/0x3cc [ 255.792285][ T1030] ? register_lock_class+0x1a30/0x1a30 [ 255.793619][ T1030] ? rcu_read_lock_sched_held+0x91/0xc0 [ 255.794963][ T1030] ? rcu_read_lock_bh_held+0xa0/0xa0 [ 255.796246][ T1030] lock_acquire+0x1b8/0x850 [ 255.797332][ T1030] ? dev_mc_sync_multiple+0xc2/0x150 [ 255.798624][ T1030] ? bond_enslave+0x3d4d/0x43e0 [bonding] [ 255.800039][ T1030] ? check_flags+0x50/0x50 [ 255.801143][ T1030] ? lock_contended+0xd80/0xd80 [ 255.802341][ T1030] _raw_spin_lock_nested+0x2e/0x70 [ 255.803592][ T1030] ? dev_mc_sync_multiple+0xc2/0x150 [ 255.804897][ T1030] dev_mc_sync_multiple+0xc2/0x150 [ 255.806168][ T1030] bond_enslave+0x3d58/0x43e0 [bonding] [ 255.807542][ T1030] ? __lock_acquire+0xe53/0x51b0 [ 255.808824][ T1030] ? bond_update_slave_arr+0xdc0/0xdc0 [bonding] [ 255.810451][ T1030] ? check_chain_key+0x236/0x5e0 [ 255.811742][ T1030] ? mutex_is_locked+0x13/0x50 [ 255.812910][ T1030] ? rtnl_is_locked+0x11/0x20 [ 255.814061][ T1030] ? netdev_master_upper_dev_get+0xf/0x120 [ 255.815553][ T1030] do_setlink+0x94c/0x3040 [ ... ] Reported-by: syzbot+4a0f7bc34e3997a6c7df@syzkaller.appspotmail.com Fixes: 1fc70edb7d7b ("net: core: add nested_level variable in net_device") Signed-off-by: Taehee Yoo Link: https://lore.kernel.org/r/20201015162606.9377-1-ap420073@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10134,7 +10134,7 @@ void netdev_run_todo(void) struct net_device *dev = list_first_entry(&unlink_list, struct net_device, unlink_list); - list_del(&dev->unlink_list); + list_del_init(&dev->unlink_list); dev->nested_level = dev->lower_level - 1; } #endif