Dear there, The self_checkpoint and self_restart are working now, but why external checkpoint cannot work.I did it like the following two ways: 1) $./onetask & $./checkpoint 4347 >img checkpoint: Device or resource busy (you may use 'ckptinfo -e' for more info) And the content in the image file is "[Error at do_checkpoint:583][err -16]Freezer cgroup failed" 2) $./onetask & $.echo 4354 > /cgroup/0/tasks $echo FROZEN > /cgroup/0/freezer.state $./checkpoint 4354 > ckpt.image checkpoint: Device or resource busy (you may use 'ckptinfo -e' for more info) And the content in the image file is "[Error at do_checkpoint:583][err -16]Freezer cgoup failed" The content in freezer.state is "FROZEN". I do not know what is wrong, can anyone can give me a hand. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers