'close()' calls 'stop()' and 'stop()' cancels pthread without any check.
Calling 'stop()' & 'close()' sequentially tries to cancel pthread twice
which will cause a crash.
Adding a state check in 'stop()' before canceling the pthread to prevent
multiple stop.
Fixes: 696fbc7bb4fc ("net/kni: remove resources when port is closed")
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Tested-by: Yinan Wang <yinan.wang@intel.com>
2ad5482b51