From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755823Ab3LSSPP (ORCPT ); Thu, 19 Dec 2013 13:15:15 -0500 Received: from lennier.cc.vt.edu ([198.82.162.213]:55256 "EHLO lennier.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754345Ab3LSSPL (ORCPT ); Thu, 19 Dec 2013 13:15:11 -0500 X-Greylist: delayed 864 seconds by postgrey-1.27 at vger.kernel.org; Thu, 19 Dec 2013 13:15:11 EST X-Mailer: exmh version 2.8.0 04/21/2012 with nmh-1.5+dev To: Eric Dumazet , netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: next-20131218 - WARNING in qdisc_list_add From: Valdis Kletnieks Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1387476879_3146P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Thu, 19 Dec 2013 13:14:39 -0500 Message-ID: <7625.1387476879@turing-police.cc.vt.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --==_Exmh_1387476879_3146P Content-Type: text/plain; charset=us-ascii Seen once while booting next-20131218 (different boot than the BUG I hit). Command that triggered it would have been one of these 2: /usr/sbin/tc qdisc add dev em1 root codel /usr/sbin/tc qdisc add dev wlp3s0 root codel It's possible that wlp3s0 wasn't there yet due to rfkill switch having nuked the wireless. 'git blame' points at the message being added in this commit: commit e57a784d8cae429f5b697fe55abf420181d9ff09 Author: Eric Dumazet Date: Thu Dec 12 15:41:56 2013 -0800 pkt_sched: set root qdisc before change() in attach_default_qdiscs() After commit 95dc19299f74 ("pkt_sched: give visibility to mq slave qdiscs") we call disc_list_add() while the device qdisc might be the noop_qdisc one. This shows up as duplicates in "tc qdisc show", as all inactive devices point to noop_qdisc. Fix this by setting dev->qdisc to the new qdisc before calling ops->change() in attach_default_qdiscs() Add a WARN_ON_ONCE() to catch any future similar problem. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller [ 153.876539] ------------[ cut here ]------------ [ 153.878667] WARNING: CPU: 1 PID: 1446 at net/sched/sch_api.c:278 qdisc_list_add+0x79/0xcf() [ 153.897042] CPU: 3 PID: 1446 Comm: tc Tainted: G O 3.13.0-rc4-next-20131218 #129 [ 153.898877] Hardware name: Dell Inc. Latitude E6530/07Y85M, BIOS A11 03/12/2013 [ 153.900666] 0000000000000000 ffff880121195950 ffffffff8164c74f 0000000000000000 [ 153.905666] ffff880121195988 ffffffff8103875e ffffffff814afe73 ffff88012828f600 [ 153.910847] 0000000000000001 ffffffff81c8cac0 0000000000000001 ffff880121195998 [ 153.916012] Call Trace: [ 153.917237] [] dump_stack+0x4f/0xa2 [ 153.918659] [] warn_slowpath_common+0x7a/0x93 [ 153.920222] [] ? qdisc_list_add+0x79/0xcf [ 153.921896] [] warn_slowpath_null+0x15/0x17 [ 153.923579] [] qdisc_list_add+0x79/0xcf [ 153.925134] [] qdisc_create+0x237/0x350 [ 153.926658] [] tc_modify_qdisc+0x486/0x4af [ 153.928173] [] rtnetlink_rcv_msg+0x180/0x193 [ 153.929753] [] ? trace_preempt_on+0x12/0x2f [ 153.931453] [] ? rtnl_newlink+0x4ba/0x4ba [ 153.933107] [] netlink_rcv_skb+0x44/0x86 [ 153.934586] [] rtnetlink_rcv+0x1e/0x25 [ 153.936133] [] netlink_unicast+0xf1/0x175 [ 153.937587] [] netlink_sendmsg+0x304/0x34e [ 153.939088] [] __sock_sendmsg_nosec+0x25/0x27 [ 153.940638] [] sock_sendmsg+0x52/0x6c [ 153.942278] [] ? might_fault+0x9b/0x9f [ 153.943980] [] ? might_fault+0x52/0x9f [ 153.945439] [] ? verify_iovec+0x5e/0xac [ 153.946993] [] ___sys_sendmsg+0x20d/0x29d [ 153.948540] [] ? arch_local_irq_save+0x9/0xc [ 153.950087] [] ? up_read+0x22/0x25 [ 153.951743] [] ? __do_page_fault+0x56f/0x600 [ 153.953495] [] ? time_hardirqs_on+0x1b/0x2f [ 153.955175] [] ? fcheck_files+0x80/0xe0 [ 153.956720] [] ? fget_light+0x30/0x90 [ 153.958195] [] __sys_sendmsg+0x3d/0x5b [ 153.959645] [] SyS_sendmsg+0xd/0x17 [ 153.961092] [] system_call_fastpath+0x16/0x1b [ 153.965229] ---[ end trace ec29ec2eecd5a461 ]--- --==_Exmh_1387476879_3146P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iQIVAwUBUrM3jwdmEQWDXROgAQKrbQ/+P9oJjyif0HRm0prl5J+//j09jovoAEuw Nqt1FI6gi6Eit13vTSsLrkJptfJ6KIKU4LVQkCrRNskp51rDHqrre7FVs5JgHCoQ j8JMAcCLYZsKNNPWt0L7QNp7z0Ps9NOdnrj/IelisBKEHkQaK0OscO7oV+r1Q4EE XDMedzqZyp+ND8/4U7g5qh3uUPVAgmeABid2WK+4ZwUtUfI7jSU3j1xQAF+hGMNT uKyC9eKPYEDWPPL2RT/B4mtZ5i9wTl+20CF6XS10l9RwH88IRo18MS5za/CO5mUm bpHS55386nw0NlNuhdW4zU/pGPXyPVvv7I/XHhgSQhi0qf2stdeBrJ4ljIxKA+mw 9w3lYjapWAYmbdl8vq1v3dyAJqgbWXQCtq0/Au99TnrRkSTMXXvbnuigDpfFweGD xLbQAyf8Uqik+itUPZxWpad0x/o5jBsCh9iXc9hxAZaNzRCzqRXXFAOCPbih9kLf oi8c2uzg6mjL3QEcLRJD5NnARRCeb0ETxbY1GbJ4o46Amavo1+aMeF5e+68BxFv1 ASDPMgs1GW0gliPjziOvJZhdSK45+INrWPYqs2+ymE1cIYILAERsoyiwIanBh+7I EdUq7slpIkZwSK76gbCxVIV+OVcC22d7OIfnykiKc6UJt4kmmatmu+CYo8VzZi33 UFQ3luOorAQ= =PSwe -----END PGP SIGNATURE----- --==_Exmh_1387476879_3146P--