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| author | Chuyi Zhou <zhouchuyi@bytedance.com> | 2023-10-18 14:17:40 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-10-19 17:02:46 -0700 |
| commit | 9c66dc94b62aef23300f05f63404afb8990920b4 (patch) | |
| tree | 9df3e5be227342647a1815c62ac0567d9bebbf61 /kernel/bpf/verifier.c | |
| parent | 6da88306811b40a207c94c9da9faf07bdb20776e (diff) | |
bpf: Introduce css_task open-coded iterator kfuncs
This patch adds kfuncs bpf_iter_css_task_{new,next,destroy} which allow
creation and manipulation of struct bpf_iter_css_task in open-coded
iterator style. These kfuncs actually wrapps css_task_iter_{start,next,
end}. BPF programs can use these kfuncs through bpf_for_each macro for
iteration of all tasks under a css.
css_task_iter_*() would try to get the global spin-lock *css_set_lock*, so
the bpf side has to be careful in where it allows to use this iter.
Currently we only allow it in bpf_lsm and bpf iter-s.
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20231018061746.111364-3-zhouchuyi@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index bb58987e4844..974713185269 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10472,6 +10472,7 @@ enum special_kfunc_type { KF_bpf_percpu_obj_new_impl, KF_bpf_percpu_obj_drop_impl, KF_bpf_throw, + KF_bpf_iter_css_task_new, }; BTF_SET_START(special_kfunc_set) @@ -10495,6 +10496,7 @@ BTF_ID(func, bpf_dynptr_clone) BTF_ID(func, bpf_percpu_obj_new_impl) BTF_ID(func, bpf_percpu_obj_drop_impl) BTF_ID(func, bpf_throw) +BTF_ID(func, bpf_iter_css_task_new) BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -10520,6 +10522,7 @@ BTF_ID(func, bpf_dynptr_clone) BTF_ID(func, bpf_percpu_obj_new_impl) BTF_ID(func, bpf_percpu_obj_drop_impl) BTF_ID(func, bpf_throw) +BTF_ID(func, bpf_iter_css_task_new) static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta) { @@ -11050,6 +11053,20 @@ static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env, &meta->arg_rbtree_root.field); } +static bool check_css_task_iter_allowlist(struct bpf_verifier_env *env) +{ + enum bpf_prog_type prog_type = resolve_prog_type(env->prog); + + switch (prog_type) { + case BPF_PROG_TYPE_LSM: + return true; + case BPF_TRACE_ITER: + return env->prog->aux->sleepable; + default: + return false; + } +} + static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta, int insn_idx) { @@ -11300,6 +11317,12 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ break; } case KF_ARG_PTR_TO_ITER: + if (meta->func_id == special_kfunc_list[KF_bpf_iter_css_task_new]) { + if (!check_css_task_iter_allowlist(env)) { + verbose(env, "css_task_iter is only allowed in bpf_lsm and bpf iter-s\n"); + return -EINVAL; + } + } ret = process_iter_arg(env, regno, insn_idx, meta); if (ret < 0) return ret; |