On 07/13/2015 11:05 PM, Nikolay Aleksandrov wrote:
> On 07/13/2015 08:57 PM, cls...@linux.vnet.ibm.com wrote:
>> From: Carol L Soto <cls...@linux.vnet.ibm.com>
>>
>> Add function bond_remove_proc_entry at __bond_release_one to avoid stack
>> trace at rmmod bonding.
>>
>> [68830.202239] remove_proc_entry: removing non-empty directory
>> 'net/bonding', leaking at least 'bond0'
>> [68830.202257] ------------[ cut here ]------------
>> [68830.202260] WARNING: at fs/proc/generic.c:562
>> [68830.202412] NIP [c0000000002abf6c] .remove_proc_entry+0x1fc/0x240
>> [68830.202416] LR [c0000000002abf68] .remove_proc_entry+0x1f8/0x240
>> [68830.202419] PACATMSCRATCH [8000000000009032]
>> [68830.202421] Call Trace:
>> [68830.202424] [c000000179277940] [c0000000002abf68]
>> .remove_proc_entry+0x1f8/0x240 (unreliable)
>> [68830.202434] [c0000001792779f0] [d0000000053229a4]
>> .bond_destroy_proc_dir+0x34/0x54 [bonding]
>> [68830.202440] [c000000179277a70] [d0000000053130e0]
>> .bond_net_exit+0x90/0x120 [bonding]
>> [68830.202445] [c000000179277b10] [c00000000059944c]
>> .ops_exit_list.isra.0+0x6c/0xd0
>> [68830.202450] [c000000179277ba0] [c000000000599774]
>> .unregister_pernet_operations+0x94/0x100
>> [68830.202454] [c000000179277c40] [c000000000599814]
>> .unregister_pernet_subsys+0x34/0x60
>> [68830.202460] [c000000179277cc0] [d000000005323758]
>> .bonding_exit+0x48/0x2328 [bonding]
>> [68830.202466] [c000000179277d30] [c00000000010dcc4]
>> .SyS_delete_module+0x1f4/0x340
>> [68830.202471] [c000000179277e30] [c000000000009e7c]
>> syscall_exit+0x0/0x7c
>> [68830.202491] ---[ end trace 9bd1d810219c9875 ]---
>>
>> Signed-off-by: Carol L Soto <cls...@linux.vnet.ibm.com>
>> ---
>> drivers/net/bonding/bond_main.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/net/bonding/bond_main.c
>> b/drivers/net/bonding/bond_main.c
>> index 19eb990..ace105a 100644
>> --- a/drivers/net/bonding/bond_main.c
>> +++ b/drivers/net/bonding/bond_main.c
>> @@ -1870,6 +1870,8 @@ static int __bond_release_one(struct net_device
>> *bond_dev,
>> dev_set_mac_address(slave_dev, &addr);
>> }
>>
>> + bond_remove_proc_entry(bond);
>> +
>> dev_set_mtu(slave_dev, slave->original_mtu);
>>
>> slave_dev->priv_flags &= ~IFF_BONDING;
>>
>
> This is incorrect, it tries to remove the bond entry on every slave release
> so if we have a bonding device with >= 2 slaves and release one of them then
> the whole bond device entry will be removed from /proc/net/bonding.
<<<<>>>>
> You can hit this case only if you had created a bonding device while doing the
> rmmod bonding (it's an old race condition which was fixed long time ago, but
> the procfs was apparently missed) and only after the notifier has been
> unregistered but before the sysfs has been removed.
>
Scratch this part, it should be triggered in a different way.
Could you provide a way to reproduce ?
> Since the bonding netdevice notifier is handling the procfs
> creation/destruction
> we could try moving the unregister after the pernet destruction which should
> help avoid such problems. Could you try the following patch:
>
>
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 19eb990d398c..d515ee38b77f 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -4682,12 +4682,10 @@ err_link:
>
> static void __exit bonding_exit(void)
> {
> - unregister_netdevice_notifier(&bond_netdev_notifier);
> -
> bond_destroy_debugfs();
> -
> bond_netlink_fini();
> unregister_pernet_subsys(&bond_net_ops);
> + unregister_netdevice_notifier(&bond_netdev_notifier);
>
> #ifdef CONFIG_NET_POLL_CONTROLLER
> /* Make sure we don't have an imbalance on our netpoll blocking */
>
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