Message-ID: <CAPWQB7Hj-W9NPEUSBBCh6Av8ri0mScs+SWCc=mc=yCQkD3w90w@mail.gmail.com>
Date:   Thu, 20 Apr 2017 11:06:43 -0700
From:   Joe Stringer <joe@....org>
To:     Mahesh Bandewar <mahesh@...dewar.net>
Cc:     Jay Vosburgh <j.vosburgh@...il.com>,
        Andy Gospodarek <andy@...yhouse.net>,
        Veaceslav Falico <vfalico@...il.com>,
        Nikolay Aleksandrov <nikolay@...hat.com>,
        David Miller <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        netdev <netdev@...r.kernel.org>,
        Mahesh Bandewar <maheshb@...gle.com>
Subject: Re: [PATCH next] bonding: fix wq initialization for links created via netlink

On 19 April 2017 at 17:30, Mahesh Bandewar <mahesh@...dewar.net> wrote:
> From: Mahesh Bandewar <maheshb@...gle.com>
>
> Earlier patch 4493b81bea ("bonding: initialize work-queues during
> creation of bond") moved the work-queue initialization from bond_open()
> to bond_create(). However this caused the link those are created using
> netlink 'create bond option' (ip link add bondX type bond); create the
> new trunk without initializing work-queues. Prior to the above mentioned
> change, ndo_open was in both paths and things worked correctly. The
> consequence is visible in the report shared by Joe Stringer -
>
> I've noticed that this patch breaks bonding within namespaces if
> you're not careful to perform device cleanup correctly.
>
> Here's my repro script, you can run on any net-next with this patch
> and you'll start seeing some weird behaviour:
>
> ip netns add foo
> ip li add veth0 type veth peer name veth0+ netns foo
> ip li add veth1 type veth peer name veth1+ netns foo
> ip netns exec foo ip li add bond0 type bond
> ip netns exec foo ip li set dev veth0+ master bond0
> ip netns exec foo ip li set dev veth1+ master bond0
> ip netns exec foo ip addr add dev bond0 192.168.0.1/24
> ip netns exec foo ip li set dev bond0 up
> ip li del dev veth0
> ip li del dev veth1
>
> The second to last command segfaults, last command hangs. rtnl is now
> permanently locked. It's not a problem if you take bond0 down before
> deleting veths, or delete bond0 before deleting veths. If you delete
> either end of the veth pair as per above, either inside or outside the
> namespace, it hits this problem.
>
> Here's some kernel logs:
> [ 1221.801610] bond0: Enslaving veth0+ as an active interface with an up link
> [ 1224.449581] bond0: Enslaving veth1+ as an active interface with an up link
> [ 1281.193863] bond0: Releasing backup interface veth0+
> [ 1281.193866] bond0: the permanent HWaddr of veth0+ -
> 16:bf:fb:e0:b8:43 - is still in use by bond0 - set the HWaddr of
> veth0+ to a different address to avoid conflicts
> [ 1281.193867] ------------[ cut here ]------------
> [ 1281.193873] WARNING: CPU: 0 PID: 2024 at kernel/workqueue.c:1511
> __queue_delayed_work+0x13f/0x150
> [ 1281.193873] Modules linked in: bonding veth openvswitch nf_nat_ipv6
> nf_nat_ipv4 nf_nat autofs4 nfsd auth_rpcgss nfs_acl binfmt_misc nfs
> lockd grace sunrpc fscache ppdev vmw_balloon coretemp psmouse
> serio_raw vmwgfx ttm drm_kms_helper vmw_vmci netconsole parport_pc
> configfs drm i2c_piix4 fb_sys_fops syscopyarea sysfillrect sysimgblt
> shpchp mac_hid nf_conntrack_ipv6 nf_defrag_ipv6 nf_conntrack_ipv4
> nf_defrag_ipv4 nf_conntrack libcrc32c lp parport hid_generic usbhid
> hid mptspi mptscsih e1000 mptbase ahci libahci
> [ 1281.193905] CPU: 0 PID: 2024 Comm: ip Tainted: G        W
> 4.10.0-bisect-bond-v0.14 #37
> [ 1281.193906] Hardware name: VMware, Inc. VMware Virtual
> Platform/440BX Desktop Reference Platform, BIOS 6.00 09/30/2014
> [ 1281.193906] Call Trace:
> [ 1281.193912]  dump_stack+0x63/0x89
> [ 1281.193915]  __warn+0xd1/0xf0
> [ 1281.193917]  warn_slowpath_null+0x1d/0x20
> [ 1281.193918]  __queue_delayed_work+0x13f/0x150
> [ 1281.193920]  queue_delayed_work_on+0x27/0x40
> [ 1281.193929]  bond_change_active_slave+0x25b/0x670 [bonding]
> [ 1281.193932]  ? synchronize_rcu_expedited+0x27/0x30
> [ 1281.193935]  __bond_release_one+0x489/0x510 [bonding]
> [ 1281.193939]  ? addrconf_notify+0x1b7/0xab0
> [ 1281.193942]  bond_netdev_event+0x2c5/0x2e0 [bonding]
> [ 1281.193944]  ? netconsole_netdev_event+0x124/0x190 [netconsole]
> [ 1281.193947]  notifier_call_chain+0x49/0x70
> [ 1281.193948]  raw_notifier_call_chain+0x16/0x20
> [ 1281.193950]  call_netdevice_notifiers_info+0x35/0x60
> [ 1281.193951]  rollback_registered_many+0x23b/0x3e0
> [ 1281.193953]  unregister_netdevice_many+0x24/0xd0
> [ 1281.193955]  rtnl_delete_link+0x3c/0x50
> [ 1281.193956]  rtnl_dellink+0x8d/0x1b0
> [ 1281.193960]  rtnetlink_rcv_msg+0x95/0x220
> [ 1281.193962]  ? __kmalloc_node_track_caller+0x35/0x280
> [ 1281.193964]  ? __netlink_lookup+0xf1/0x110
> [ 1281.193966]  ? rtnl_newlink+0x830/0x830
> [ 1281.193967]  netlink_rcv_skb+0xa7/0xc0
> [ 1281.193969]  rtnetlink_rcv+0x28/0x30
> [ 1281.193970]  netlink_unicast+0x15b/0x210
> [ 1281.193971]  netlink_sendmsg+0x319/0x390
> [ 1281.193974]  sock_sendmsg+0x38/0x50
> [ 1281.193975]  ___sys_sendmsg+0x25c/0x270
> [ 1281.193978]  ? mem_cgroup_commit_charge+0x76/0xf0
> [ 1281.193981]  ? page_add_new_anon_rmap+0x89/0xc0
> [ 1281.193984]  ? lru_cache_add_active_or_unevictable+0x35/0xb0
> [ 1281.193985]  ? __handle_mm_fault+0x4e9/0x1170
> [ 1281.193987]  __sys_sendmsg+0x45/0x80
> [ 1281.193989]  SyS_sendmsg+0x12/0x20
> [ 1281.193991]  do_syscall_64+0x6e/0x180
> [ 1281.193993]  entry_SYSCALL64_slow_path+0x25/0x25
> [ 1281.193995] RIP: 0033:0x7f6ec122f5a0
> [ 1281.193995] RSP: 002b:00007ffe69e89c48 EFLAGS: 00000246 ORIG_RAX:
> 000000000000002e
> [ 1281.193997] RAX: ffffffffffffffda RBX: 00007ffe69e8dd60 RCX: 00007f6ec122f5a0
> [ 1281.193997] RDX: 0000000000000000 RSI: 00007ffe69e89c90 RDI: 0000000000000003
> [ 1281.193998] RBP: 00007ffe69e89c90 R08: 0000000000000000 R09: 0000000000000003
> [ 1281.193999] R10: 00007ffe69e89a10 R11: 0000000000000246 R12: 0000000058f14b9f
> [ 1281.193999] R13: 0000000000000000 R14: 00000000006473a0 R15: 00007ffe69e8e450
> [ 1281.194001] ---[ end trace 713a77486cbfbfa3 ]---
>
> Fixes: 4493b81bea ("bonding: initialize work-queues during creation of bond")
> Reported-by: Joe Stringer <joe@....org>
> Signed-off-by: Mahesh Bandewar <maheshb@...gle.com>
> ---

Thanks Mahesh, this fixes the issue I was observing.

Tested-by: Joe Stringer <joe@....org>

>  drivers/net/bonding/bond_main.c    | 2 +-
>  drivers/net/bonding/bond_netlink.c | 5 +++++
>  include/net/bonding.h              | 1 +
>  3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 6bd3b50faf48..e549bf6f5cac 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -3243,7 +3243,7 @@ u32 bond_xmit_hash(struct bonding *bond, struct sk_buff *skb)
>
>  /*-------------------------- Device entry points ----------------------------*/
>
> -static void bond_work_init_all(struct bonding *bond)
> +void bond_work_init_all(struct bonding *bond)
>  {
>         INIT_DELAYED_WORK(&bond->mcast_work,
>                           bond_resend_igmp_join_requests_delayed);
> diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
> index b8df0f5e8c25..31b9f37c7dbd 100644
> --- a/drivers/net/bonding/bond_netlink.c
> +++ b/drivers/net/bonding/bond_netlink.c
> @@ -449,6 +449,11 @@ static int bond_newlink(struct net *src_net, struct net_device *bond_dev,
>         err = register_netdevice(bond_dev);
>
>         netif_carrier_off(bond_dev);
> +       if (err >= 0) {

register_netdevice() returns 0 on success according to its
documentation, does it need to handle positive err values?

> +               struct bonding *bond = netdev_priv(bond_dev);
> +
> +               bond_work_init_all(bond);
> +       }
>
>         return err;
>  }
> diff --git a/include/net/bonding.h b/include/net/bonding.h
> index 04a21e8048be..b00508d22e0a 100644
> --- a/include/net/bonding.h
> +++ b/include/net/bonding.h
> @@ -614,6 +614,7 @@ struct bond_vlan_tag *bond_verify_device_path(struct net_device *start_dev,
>                                               int level);
>  int bond_update_slave_arr(struct bonding *bond, struct slave *skipslave);
>  void bond_slave_arr_work_rearm(struct bonding *bond, unsigned long delay);
> +void bond_work_init_all(struct bonding *bond);
>
>  #ifdef CONFIG_PROC_FS
>  void bond_create_proc_entry(struct bonding *bond);
> --
> 2.12.2.816.g2cccc81164-goog
>

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