From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Aleksandrov Subject: Re: [PATCH net] bonding: fix destruction of bond with devices different from arphrd_ether Date: Thu, 16 Jul 2015 00:54:06 +0200 Message-ID: <55A6E48E.3020206@cumulusnetworks.com> References: <55A69D17.5030800@cumulusnetworks.com> <1436989971-32761-1-git-send-email-razor@blackwall.org> <87io9lcag3.fsf@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, j.vosburgh@gmail.com, gospo@cumulusnetworks.com, vfalico@gmail.com, clsoto@linux.vnet.ibm.com, davem@davemloft.net To: "Eric W. Biederman" , Nikolay Aleksandrov Return-path: Received: from mail-wg0-f52.google.com ([74.125.82.52]:33973 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753501AbbGOWyL (ORCPT ); Wed, 15 Jul 2015 18:54:11 -0400 Received: by wgkl9 with SMTP id l9so44606535wgk.1 for ; Wed, 15 Jul 2015 15:54:09 -0700 (PDT) In-Reply-To: <87io9lcag3.fsf@x220.int.ebiederm.org> Sender: netdev-owner@vger.kernel.org List-ID: On 07/16/2015 12:39 AM, Eric W. Biederman wrote: > Nikolay Aleksandrov writes: > >> From: Nikolay Aleksandrov >> >> When the bonding is being unloaded and the netdevice notifier is >> unregistered it executes NETDEV_UNREGISTER for each device which should >> remove the bond's proc entry but if the device enslaved is not of >> ARPHRD_ETHER type and is in front of the bonding, it may execute >> bond_release_and_destroy() first which would release the last slave and >> destroy the bond device leaving the proc entry and thus we will get the >> following error (with dynamic debug on for bond_netdev_event to see the >> events order): > > I see the failure below. I am perplexed at the description. Does the > bonding driver actually make sense on a non-ethernet device? > Sometimes it does, I've seen it used with infiniband devices a lot, also there were cases of some ppp users. > Would it not be better to make more sense to limit bonding to ethernet > devices so we don't get weird behavior? I imagine there might be other > problems with bonding non-ethernet devices that no one has spotted, > or cares about. > > Eric > > My personal opinion would be to disable non-ethernet devices, but support was already added and has been there for a long time so we have to fix this for the older releases, I don't mind removing non-ethernet device support for net-next but I'm guessing there're people still using that like the case that started this thread. Cheers, Nik >> [ 908.963051] eql: event: 9 >> [ 908.963052] eql: IFF_SLAVE >> [ 908.963054] eql: event: 2 >> [ 908.963056] eql: IFF_SLAVE >> [ 908.963058] eql: event: 6 >> [ 908.963059] eql: IFF_SLAVE >> [ 908.963110] bond0: Releasing active interface eql >> [ 908.976168] bond0: Destroying bond bond0 >> [ 908.976266] bond0 (unregistering): Released all slaves >> [ 908.984097] ------------[ cut here ]------------ >> [ 908.984107] WARNING: CPU: 0 PID: 1787 at fs/proc/generic.c:575 >> remove_proc_entry+0x112/0x160() >> [ 908.984110] remove_proc_entry: removing non-empty directory >> 'net/bonding', leaking at least 'bond0' >> [ 908.984111] Modules linked in: bonding(-) eql(O) 9p nfsd auth_rpcgss >> oid_registry nfs_acl nfs lockd grace fscache sunrpc crct10dif_pclmul >> crc32_pclmul crc32c_intel ghash_clmulni_intel ppdev qxl drm_kms_helper >> snd_hda_codec_generic aesni_intel ttm aes_x86_64 glue_helper pcspkr lrw >> gf128mul ablk_helper cryptd snd_hda_intel virtio_console snd_hda_codec >> psmouse serio_raw snd_hwdep snd_hda_core 9pnet_virtio 9pnet evdev joydev >> drm virtio_balloon snd_pcm snd_timer snd soundcore i2c_piix4 i2c_core >> pvpanic acpi_cpufreq parport_pc parport processor thermal_sys button >> autofs4 ext4 crc16 mbcache jbd2 hid_generic usbhid hid sg sr_mod cdrom >> ata_generic virtio_blk virtio_net floppy ata_piix e1000 libata ehci_pci >> virtio_pci scsi_mod uhci_hcd ehci_hcd virtio_ring virtio usbcore >> usb_common [last unloaded: bonding] >> >> [ 908.984168] CPU: 0 PID: 1787 Comm: rmmod Tainted: G W O >> 4.2.0-rc2+ #8 >> [ 908.984170] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 >> [ 908.984172] 0000000000000000 ffffffff81732d41 ffffffff81525b34 >> ffff8800358dfda8 >> [ 908.984175] ffffffff8106c521 ffff88003595af78 ffff88003595af40 >> ffff88003e3a4280 >> [ 908.984178] ffffffffa058d040 0000000000000000 ffffffff8106c59a >> ffffffff8172ebd0 >> [ 908.984181] Call Trace: >> [ 908.984188] [] ? dump_stack+0x40/0x50 >> [ 908.984193] [] ? warn_slowpath_common+0x81/0xb0 >> [ 908.984196] [] ? warn_slowpath_fmt+0x4a/0x50 >> [ 908.984199] [] ? remove_proc_entry+0x112/0x160 >> [ 908.984205] [] ? bond_destroy_proc_dir+0x26/0x30 >> [bonding] >> [ 908.984208] [] ? bond_net_exit+0x8e/0xa0 [bonding] >> [ 908.984217] [] ? ops_exit_list.isra.4+0x37/0x70 >> [ 908.984225] [] ? >> unregister_pernet_operations+0x8d/0xd0 >> [ 908.984228] [] ? >> unregister_pernet_subsys+0x1d/0x30 >> [ 908.984232] [] ? bonding_exit+0x23/0xdba [bonding] >> [ 908.984236] [] ? SyS_delete_module+0x18a/0x250 >> [ 908.984241] [] ? task_work_run+0x89/0xc0 >> [ 908.984244] [] ? >> entry_SYSCALL_64_fastpath+0x16/0x75 >> [ 908.984247] ---[ end trace 7c006ed4abbef24b ]--- >> >> Thus remove the proc entry manually if bond_release_and_destroy() is >> used. Because of the checks in bond_remove_proc_entry() it's not a >> problem for a bond device to change namespaces (the bug fixed by the >> Fixes commit) but since commit >> f9399814927ad ("bonding: Don't allow bond devices to change network >> namespaces.") that can't happen anyway. >> >> Reported-by: Carol Soto >> Signed-off-by: Nikolay Aleksandrov >> Fixes: a64d49c3dd50 ("bonding: Manage /proc/net/bonding/ entries from >> the netdev events") >> --- >> drivers/net/bonding/bond_main.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c >> index 317a49480475..ec1404ec4d2f 100644 >> --- a/drivers/net/bonding/bond_main.c >> +++ b/drivers/net/bonding/bond_main.c >> @@ -1916,6 +1916,7 @@ static int bond_release_and_destroy(struct net_device *bond_dev, >> bond_dev->priv_flags |= IFF_DISABLE_NETPOLL; >> netdev_info(bond_dev, "Destroying bond %s\n", >> bond_dev->name); >> + bond_remove_proc_entry(bond); >> unregister_netdevice(bond_dev); >> } >> return ret;