[PATCH OLK-6.6 1/4] cgroup: make cgroup_bpf_prog_attach work when cgroup2 is not mounted

From: Liu Jian liujian56@huawei.com

hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8J90J

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BPF_PROG_TYPE_CGROUP* bpf programs is associated with cgroup2. If cgroup2 is not mounted, the bpf program is associated with cgrp_dfl_root.cgrp by default.

Then we can use it like below: bpftool cgroup attach /sys/fs/cgroup/cpu sock_ops pinned /sys/fs/bpf/xxx

Signed-off-by: Liu Jian liujian56@huawei.com Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com --- include/linux/cgroup.h | 1 + kernel/bpf/cgroup.c | 8 ++++---- kernel/cgroup/cgroup.c | 22 ++++++++++++++++++++++ 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b307013b9c6c..8b37ad6ddb46 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -107,6 +107,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,

struct cgroup *cgroup_get_from_path(const char *path); struct cgroup *cgroup_get_from_fd(int fd); +struct cgroup *cgroup_get_from_fd_v2(int fd); struct cgroup *cgroup_v1v2_get_from_fd(int fd);

int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 03b3d4492980..8591c1da3a21 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1134,7 +1134,7 @@ int cgroup_bpf_prog_attach(const union bpf_attr *attr, struct cgroup *cgrp; int ret;

- cgrp = cgroup_get_from_fd(attr->target_fd); + cgrp = cgroup_get_from_fd_v2(attr->target_fd); if (IS_ERR(cgrp)) return PTR_ERR(cgrp);

@@ -1162,7 +1162,7 @@ int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) struct cgroup *cgrp; int ret;

- cgrp = cgroup_get_from_fd(attr->target_fd); + cgrp = cgroup_get_from_fd_v2(attr->target_fd); if (IS_ERR(cgrp)) return PTR_ERR(cgrp);

@@ -1281,7 +1281,7 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) if (attr->link_create.flags) return -EINVAL;

- cgrp = cgroup_get_from_fd(attr->link_create.target_fd); + cgrp = cgroup_get_from_fd_v2(attr->link_create.target_fd); if (IS_ERR(cgrp)) return PTR_ERR(cgrp);

@@ -1321,7 +1321,7 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, struct cgroup *cgrp; int ret;

- cgrp = cgroup_get_from_fd(attr->query.target_fd); + cgrp = cgroup_get_from_fd_v2(attr->query.target_fd); if (IS_ERR(cgrp)) return PTR_ERR(cgrp);

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1fb7f562289d..beff7f47ea82 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6899,6 +6899,28 @@ struct cgroup *cgroup_get_from_fd(int fd) } EXPORT_SYMBOL_GPL(cgroup_get_from_fd);

+/** + * same with cgroup_get_from_fd, only add cgrp_dfl_visible check + */ +struct cgroup *cgroup_get_from_fd_v2(int fd) +{ + struct cgroup *cgrp = cgroup_v1v2_get_from_fd(fd); + + if (IS_ERR(cgrp)) + return ERR_CAST(cgrp); + + if (!cgroup_on_dfl(cgrp)) { + cgroup_put(cgrp); + if (cgrp_dfl_visible) + return ERR_PTR(-EBADF); + + cgrp = &cgrp_dfl_root.cgrp; + cgroup_get(cgrp); + } + return cgrp; +} +EXPORT_SYMBOL_GPL(cgroup_get_from_fd_v2); + static u64 power_of_ten(int power) { u64 v = 1;