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List:       linux-wireless
Subject:    Re: [PATCH net v4 03/12] bonding: fix unexpected IFF_BONDING bit unset
From:       Jay Vosburgh <jay.vosburgh () canonical ! com>
Date:       2019-09-30 20:48:55
Message-ID: 26315.1569876535 () famine
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Taehee Yoo <ap420073@gmail.com> wrote:

> The IFF_BONDING means bonding master or bonding slave device.
> ->ndo_add_slave() sets IFF_BONDING flag and ->ndo_del_slave() unsets
> IFF_BONDING flag.
> 
> bond0<--bond1
> 
> Both bond0 and bond1 are bonding device and these should keep having
> IFF_BONDING flag until they are removed.
> But bond1 would lose IFF_BONDING at ->ndo_del_slave() because that routine
> do not check whether the slave device is the bonding type or not.
> This patch adds the interface type check routine before removing
> IFF_BONDING flag.
> 
> Test commands:
> ip link add bond0 type bond
> ip link add bond1 type bond
> ip link set bond1 master bond0
> ip link set bond1 nomaster
> ip link del bond1 type bond
> ip link add bond1 type bond
> 
> Splat looks like:
> [   38.843933] proc_dir_entry 'bonding/bond1' already registered                    \
>  [   38.844741] WARNING: CPU: 1 PID: 631 at fs/proc/generic.c:361 \
> proc_register+0x2a9/0x3e0                                [   38.845741] Modules \
> linked in: bonding ip_tables x_tables                                               \
>  [   38.846432] CPU: 1 PID: 631 Comm: ip Not tainted 5.3.0+ #3                      \
>  [   38.847234] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox \
> 12/01/2006                              [   38.848489] RIP: \
> 0010:proc_register+0x2a9/0x3e0                                                      \
>  [   38.849164] Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 39 01 00 00 48 8b 04 24 \
> 48 89 ea 48 c7 c7 e0 2b 34 b3 48 8b b0 e 0 00 00 00 e8 c7 b6 89 ff <0f> 0b 48 c7 c7 \
> 40 3d c5 b3 e8 99 7a 38 01 48 8b 4c 24 10 48 b8 00                             [   \
> 38.851317] RSP: 0018:ffff888061527078 EFLAGS: 00010282 [   38.851902] RAX: \
> dffffc0000000008 RBX: ffff888064dc8cb0 RCX: ffffffffb1d252a2 [   38.852684] RDX: \
> 0000000000000001 RSI: 0000000000000008 RDI: ffff88806cbf6b8c [   38.853464] RBP: \
> ffff888064dc8f33 R08: ffffed100d980019 R09: ffffed100d980019 [   38.854242] R10: \
> 0000000000000001 R11: ffffed100d980018 R12: ffff888064dc8e48 [   38.855929] R13: \
> ffff888064dc8f32 R14: dffffc0000000000 R15: ffffed100c9b91e6 [   38.856695] FS:  \
> 00007fc9fcc230c0(0000) GS:ffff88806ca00000(0000) knlGS:0000000000000000 [   \
> 38.857541] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [   38.858150] CR2: \
> 000055948b91c118 CR3: 0000000057110006 CR4: 00000000000606e0 [   38.858957] DR0: \
> 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [   38.859785] DR3: \
> 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [   38.860700] Call \
> Trace:                              [   38.861004]  \
> proc_create_seq_private+0xb3/0xf0 [   38.861460]  \
> bond_create_proc_entry+0x1b3/0x3f0 [bonding] [   38.862113]  \
> bond_netdev_event+0x433/0x970 [bonding] [   38.862762]  ? \
> __module_text_address+0x13/0x140 [   38.867678]  notifier_call_chain+0x90/0x160
> [   38.868257]  register_netdevice+0x9b3/0xd80
> [   38.868791]  ? alloc_netdev_mqs+0x854/0xc10  
> [   38.869335]  ? netdev_change_features+0xa0/0xa0
> [   38.869852]  ? rtnl_create_link+0x2ed/0xad0
> [   38.870423]  bond_newlink+0x2a/0x60 [bonding]
> [   38.870935]  __rtnl_newlink+0xb9f/0x11b0
> [ ... ]
> Fixes: 0b680e753724 ("[PATCH] bonding: Add priv_flag to avoid event mishandling")
> Signed-off-by: Taehee Yoo <ap420073@gmail.com>

Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>

> ---
> 
> v2 -> v4 :
> - This patch is not changed
> v1 -> v2 :
> - Do not add a new priv_flag.
> 
> drivers/net/bonding/bond_main.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 931d9d935686..0db12fcfc953 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -1816,7 +1816,8 @@ int bond_enslave(struct net_device *bond_dev, struct \
> net_device *slave_dev,  slave_disable_netpoll(new_slave);
> 
> err_close:
> -	slave_dev->priv_flags &= ~IFF_BONDING;
> +	if (!netif_is_bond_master(slave_dev))
> +		slave_dev->priv_flags &= ~IFF_BONDING;
> 	dev_close(slave_dev);
> 
> err_restore_mac:
> @@ -2017,7 +2018,8 @@ static int __bond_release_one(struct net_device *bond_dev,
> 	else
> 		dev_set_mtu(slave_dev, slave->original_mtu);
> 
> -	slave_dev->priv_flags &= ~IFF_BONDING;
> +	if (!netif_is_bond_master(slave_dev))
> +		slave_dev->priv_flags &= ~IFF_BONDING;
> 
> 	bond_free_slave(slave);
> 
> -- 
> 2.17.1
> 


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