Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932615AbcDNOoe (ORCPT ); Thu, 14 Apr 2016 10:44:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:42460 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754591AbcDNOoc (ORCPT ); Thu, 14 Apr 2016 10:44:32 -0400 Date: Thu, 14 Apr 2016 16:44:23 +0200 (CEST) From: Jiri Kosina X-X-Sender: jkosina@pobox.suse.cz To: Jamal Hadi Salim cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Deleting child qdisc doesn't reset parent to default qdisc? Message-ID: User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1493 Lines: 42 Hi, I've came across the behavior where adding a child qdisc and then deleting it again makes the networking dysfunctional (I guess that's because all of a sudden there is absolutely no working qdisc on the device, although there originally was a default one in the parent). In a nutshell, is this expected behavior or bug? ===== jikos:~ # tc qdisc show qdisc tbf 10: dev eth0 root refcnt 2 rate 800Mbit burst 131000b lat 1.0ms jikos:~ # ping -c 1 nix.cz | head -2 PING nix.cz (195.47.235.3) 56(84) bytes of data. 64 bytes from info.nix.cz (195.47.235.3): icmp_seq=1 ttl=89 time=1.59 ms jikos:~ # tc qdisc add dev eth0 parent 10:1 sfq jikos:~ # tc qdisc show qdisc tbf 10: dev eth0 root refcnt 2 rate 800Mbit burst 131000b lat 1.0ms qdisc sfq 8008: dev eth0 parent 10:1 limit 127p quantum 1514b depth 127 divisor 1024 jikos:~ # ping -c 1 nix.cz | head -2 PING nix.cz (195.47.235.3) 56(84) bytes of data. 64 bytes from info.nix.cz (195.47.235.3): icmp_seq=1 ttl=89 time=1.67 ms jikos:~ # tc qdisc del dev eth0 parent 10:1 sfq jikos:~ # tc qdisc show qdisc tbf 10: dev eth0 root refcnt 2 rate 800Mbit burst 131000b lat 1.0ms jikos:~ # ping -c 1 nix.cz | head -2 PING nix.cz (195.47.235.3) 56(84) bytes of data. [ ... nothing happens ... ] ^C jikos:~ # tc qdisc add dev eth0 parent 10:1 sfq jikos:~ # ping -c 1 nix.cz | head -2 PING nix.cz (195.47.235.3) 56(84) bytes of data. 64 bytes from info.nix.cz (195.47.235.3): icmp_seq=1 ttl=89 time=1.66 ms ===== Thanks, -- Jiri Kosina