Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751746AbdIJTNv (ORCPT ); Sun, 10 Sep 2017 15:13:51 -0400 Received: from mx3.wp.pl ([212.77.101.9]:54109 "EHLO mx3.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810AbdIJTNu (ORCPT ); Sun, 10 Sep 2017 15:13:50 -0400 Date: Sun, 10 Sep 2017 21:13:45 +0200 From: Jakub Kicinski To: Greg Kroah-Hartman Cc: Dmitry Torokhov , LKML Subject: Re: [bisected] Re: Module removal-related regression? Message-ID: <20170910211345.5da116ba@cakuba.netronome.com> In-Reply-To: <20170910190908.GA5164@kroah.com> References: <20170909194121.39cd9f56@cakuba.netronome.com> <20170909212732.5bc98775@cakuba.netronome.com> <20170909221726.241c29f6@cakuba.netronome.com> <20170910000338.093aa04e@cakuba.netronome.com> <20170910162111.GA17387@dtor-ws> <20170910200010.4ad7a032@cakuba.netronome.com> <8D38F5B5-C5EA-4436-91CB-B302A42A78F0@gmail.com> <20170910190908.GA5164@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-WP-MailID: ec2efa1a8b955cdf66d09c528b22608a X-WP-AV: skaner antywirusowy Poczty Wirtualnej Polski X-WP-SPAM: NO 000000A [UZP0] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4421 Lines: 105 On Sun, 10 Sep 2017 21:09:08 +0200, Greg Kroah-Hartman wrote: > On Sun, Sep 10, 2017 at 11:12:17AM -0700, Dmitry Torokhov wrote: > > On September 10, 2017 11:00:10 AM PDT, Jakub Kicinski wrote: > > >On Sun, 10 Sep 2017 09:21:11 -0700, Dmitry Torokhov wrote: > > >> On Sun, Sep 10, 2017 at 12:03:38AM +0200, Jakub Kicinski wrote: > > >> > On Sat, 09 Sep 2017 13:59:25 -0700, Dmitry Torokhov wrote: > > >> > > On September 9, 2017 1:17:26 PM PDT, Jakub Kicinski > > > wrote: > > >> > > >On Sat, 9 Sep 2017 12:55:51 -0700, Dmitry Torokhov wrote: > > >> > > >> On Sat, Sep 9, 2017 at 12:27 PM, Jakub Kicinski > > > > > >> > > >wrote: > > >> > > >> > On Sat, 9 Sep 2017 19:41:21 +0200, Jakub Kicinski wrote: > > > > > >> > > >> >> Hi! > > >> > > >> >> > > >> > > >> >> I'm having trouble with modules on linux/master. rmmod > > >succeeds > > >> > > >but the > > >> > > >> >> module is still loaded and the refcount goes to 1: > > >> > > >> >> > > >> > > >> >> #rmmod nfp; insmod ./src/nfp.ko nfp_pf_netdev=0 ; \ > > >> > > >> >> /opt/netronome/bin/nfp-hwinfo -n 2 assembly.partno \ > > >> > > >> >> lsmod | grep nfp; \ > > >> > > >> >> rmmod nfp; \ > > >> > > >> >> lsmod | grep nfp > > >> > > >> >> nfp 249856 0 > > >> > > >> >> nfp 200704 1 > > >> > > >> >> > > >> > > >> >> If I rmmod again the module will be actually unloaded. The > > >user > > >> > > >space > > >> > > >> >> is mostly Ubuntu 14.04. Has anyone seen this? I'm trying > > >to > > >> > > >bisect > > >> > > >> >> now... > > >> > > >> > > > >> > > >> > Got 'em! > > >> > > >> > > > >> > > >> > commit 1455cf8dbfd06aa7651dcfccbadb7a093944ca65 (HEAD, > > >> > > >refs/bisect/bad) > > >> > > >> > Author: Dmitry Torokhov > > >> > > >> > Date: Wed Jul 19 17:24:30 2017 -0700 > > >> > > >> > > > >> > > >> > driver core: emit uevents when device is bound to a > > >driver > > >> > > >> > > >> > > >> Does it happen with all modules or only nfp one? > > >> > > >> > > >> > > >> It seems to work here: > > >> > > >> > > >> > > >> dtor@dtor-glaptop3:~ $ lsmod | grep psmouse > > >> > > >> psmouse 135168 0 > > >> > > >> dtor@dtor-glaptop3:~ $ sudo rmmod psmouse > > >> > > >> dtor@dtor-glaptop3:~ $ lsmod | grep psmouse > > >> > > >> dtor@dtor-glaptop3:~ $ sudo modprobe psmouse > > >> > > > > > >> > > >It looks like the driver is actually reloaded. The driver used > > >to > > >> > > >return EPROBE_DEFER, but I think it doesn't any more (rebuilding > > >the > > >> > > >kernel to test that right now). > > >> > > > > > >> > > >Could the uevent on unbind tickle Ubuntu 14.04's udev or somehow > > >> > > >else cause the driver to be loaded again? > > >> > > > > >> > > It depends on how silly the udev rules are, but yes, this can > > >definitely happen. > > >> > > > >> > I confirmed the driver doesn't use EPROBE_DEFER any more: > > >> > > > >> > $ grep -nrI EPROBE_DEFER drivers/net/ethernet/netronome/ > > >> > $ > > >> > > >> Not sure why you bring the deferrals here, they have nothing to do > > >with > > >> module removal. Also, deferrals are rarely issued by the leaf driver, > > >and > > >> more often by providers of resources (GPIO, regulator, interrupt, > > >etc). > > > > > >Yes, it's unusual, but this driver used to do it. Which is exactly why > > >I brought it up. Turns out it was irrelevant :) > > > > > >> > I tested without any udev rules in /etc/udev/, just the standard > > >distro > > >> > ones. Same thing. > > >> > > >> Right, so this is the default udev rule: > > >> > > >> /lib/udev/rules.d/80-drivers.rules: > > >> > > >> # do not edit this file, it will be overwritten on update > > >> > > >> ACTION=="remove", GOTO="drivers_end" > > >> > > >> ENV{MODALIAS}=="?*", RUN{builtin}="kmod load $env{MODALIAS}" > > So if the new uevents do not have the MODALIAS line in them, then they > will not trigger this? Dmitry, can you see if that would fix this > problem without having to fix everyone's old versions of udev/systemd? Perhaps another option is dropping the unbind event? From the commit message it seems like only bind is really needed ATM. Do events have to be symmetrical?