[PATCH v3 bpf-next 3/4] bpf: Mark cgroup_subsys_state->cgroup RCU safe
From: Song Liu <song@kernel.org>
Date: 2025-06-23 06:39:19
Also in:
bpf, linux-fsdevel, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Mark struct cgroup_subsys_state->cgroup as safe under RCU read lock. This will enable accessing css->cgroup from a bpf css iterator. Signed-off-by: Song Liu <song@kernel.org> --- kernel/bpf/verifier.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 279a64933262..e2f53dc8766a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c@@ -7058,6 +7058,10 @@ BTF_TYPE_SAFE_RCU(struct css_set) { struct cgroup *dfl_cgrp; }; +BTF_TYPE_SAFE_RCU(struct cgroup_subsys_state) { + struct cgroup *cgroup; +}; + /* RCU trusted: these fields are trusted in RCU CS and can be NULL */ BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) { struct file __rcu *exe_file;
@@ -7108,6 +7112,7 @@ static bool type_is_rcu(struct bpf_verifier_env *env, BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct task_struct)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct css_set)); + BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup_subsys_state)); return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu"); }
--
2.47.1