[dpdk-dev] Question about bonding mode set API

["Min Hu (Connor)" <humin29@huawei.com>]

Hi, all,
	I met one questions:
when I start testpmd, and type command like this, it will
lead to Segmentation fault, like:

testpmd> create bonded device 4 0
testpmd> add bonding slave 0 2
testpmd> add bonding slave 1 2
testpmd> port start 2
testpmd> set bonding mode 0 2
testpmd> quit
Stopping port 0...
Stopping ports...
Please remove port 0 from bonded device.
Done

Stopping port 1...
Stopping ports...
Please remove port 1 from bonded device.
Done

Stopping port 2...
Stopping ports...
Done

Shutting down port 0...
Closing ports...
Please remove port 0 from bonded device.
Done

Shutting down port 1...
Closing ports...
Please remove port 1 from bonded device.
Done

Shutting down port 2...
Closing ports...
0000:7d:00.0 hns3_dev_close(): Close port 0 finished
Port 0 is closed
0000:7d:00.1 hns3_dev_close(): Close port 1 finished
Port 1 is closed
Port 2 is closed
Done

Bye...
Segmentation fault

***************
The reason to the bug is that rte timer do not be cancelled when quit.
That is,
in 'bond_ethdev_start', resources are alloced according to different
bonding mode.
in 'bond_ethdev_stop', resources are free by the corresponding mode.

For example, 'bond_ethdev_start' start bond_mode_8023ad_ext_periodic_cb
timer for bonding mode 4. and 'bond_ethdev_stop' cancel the timer only 
when the current bonding mode is 4.
If the bonding mode is changed(not 4), and directly quit the process,
the timer will still on, and freed memory will be accessed, then 
segmentation fault.

***********
That is just one bug for doing that, any bugs such as
memory leakage will occur. In my opinion, I think that operation is
not permitted. we should standardized usage of the API.
When we want to use 'bond_ethdev_mode_set', we should do like that
order:
bond_ethdev_stop
bond_ethdev_mode_set
bond_ethdev_start

Because 'bonding mode'changed means resources changed, we should
reallocate resources for different mode.

What is your opinion? wish your reply.
	 Best regards.