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From: Djalal Harouni <tixxdz@gmail.com>
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Cc: Tejun Heo <tj@kernel.org>,
	Zefan Li <lizefan.x@bytedance.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
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	Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
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	Hao Luo <haoluo@google.com>,
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	Mykola Lysenko <mykolal@fb.com>,
	Shuah Khan <shuah@kernel.org>,
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	bpf@vger.kernel.org,
	linux-kselftest@vger.kernel.org
Subject: [RFC PATCH bpf-next 0/3] bpf: freeze a task cgroup from bpf
Date: Wed, 27 Mar 2024 23:53:22 +0100
Message-Id: <20240327225334.58474-1-tixxdz@gmail.com>
In-Reply-To: <20240327-ccb56fc7a6e80136db80876c@djalal>
References: <20240327-ccb56fc7a6e80136db80876c@djalal>
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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

 include/linux/cgroup.h                                      |   2 ++
 kernel/bpf/helpers.c                                        |  31 ++++
 kernel/cgroup/cgroup.c                                      |  67 ++++++++
 tools/testing/selftests/bpf/prog_tests/task_freeze_cgroup.c | 165 +++++++++++++++++++++
 tools/testing/selftests/bpf/progs/test_task_freeze_cgroup.c | 110 ++++++++++++++
 5 files changed, 375 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/task_freeze_cgroup.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_task_freeze_cgroup.c

-- 
2.34.1