On Thu, Mar 28, 2024 at 10:22 AM Tejun Heo <tj@xxxxxxxxxx> wrote: > > Hello, Djalal. > > On Wed, Mar 27, 2024 at 11:53:22PM +0100, Djalal Harouni wrote: > > This patch series adds support to freeze the task cgroup hierarchy > > that is on a default cgroup v2 without going through kernfs interface. > > > > For some cases we want to freeze the cgroup of a task based on some > > signals, doing so from bpf is better than user space which could be > > too late. > > > > Planned users of this feature are: tetragon and systemd when freezing > > a cgroup hierarchy that could be a K8s pod, container, system service > > or a user session. > > > > Patch 1: cgroup: add cgroup_freeze_no_kn() to freeze a cgroup from bpf > > Patch 2: bpf: add bpf_task_freeze_cgroup() to freeze the cgroup of a task > > Patch 3: selftests/bpf: add selftest for bpf_task_freeze_cgroup > > It bothers me a bit that it's adding a dedicated interface for something > which already has a defined userspace interface. Would it be better to have > kfunc wrappers for kernel_read() and kernel_write()? How would that look ? prog cannot and shouldn't open a file. The seq_file would be passed/pinned by user space?
