On Thu, May 4, 2023 at 11:08 PM Feng zhou <zhoufeng.zf@xxxxxxxxxxxxx> wrote: > > From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx> > > test_progs: > Tests new kfunc bpf_task_under_cgroup(). > > The bpf program saves the new task's pid within a given cgroup to > the remote_pid, which is convenient for the user-mode program to > verify the test correctness. > > The user-mode program creates its own mount namespace, and mounts the > cgroupsv2 hierarchy in there, call the fork syscall, then check if > remote_pid and local_pid are unequal. > > Signed-off-by: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx> > Acked-by: Yonghong Song <yhs@xxxxxx> > --- Hi Feng, I have a comment about the methodology of the test, but the patch looks ok to me. Why do we have to test via a tracing program? I think what we need is just a task and a cgroup. Since we have the kfunc bpf_task_from_pid() and bpf_cgroup_from_id(), we can write a syscall program which takes a pid and a cgroup id as input and get the task and cgroup objects directly in the program. I like testing via a syscall program because it doesn't depend on the newtask tracepoint and it should be simpler. But I'm ok with the current version of the patch, just have some thoughts. Hao
