diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index cb3c6b3b89c80..9f100fc422c33 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -72,10 +73,16 @@ struct cgroup_bpf { /* temp storage for effective prog array used by prog_attach/detach */ struct bpf_prog_array __rcu *inactive; + + /* reference counter used to detach bpf programs after cgroup removal */ + struct percpu_ref refcnt; + + /* cgroup_bpf is released using a work queue */ + struct work_struct release_work; }; -void cgroup_bpf_put(struct cgroup *cgrp); int cgroup_bpf_inherit(struct cgroup *cgrp); +void cgroup_bpf_offline(struct cgroup *cgrp); int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type, u32 flags); @@ -283,8 +290,8 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, struct bpf_prog; struct cgroup_bpf {}; -static inline void cgroup_bpf_put(struct cgroup *cgrp) {} static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } +static inline void cgroup_bpf_offline(struct cgroup *cgrp) {} static inline int cgroup_bpf_prog_attach(const union bpf_attr *attr, enum bpf_prog_type ptype, diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c0077adeea833..49e8facf7c4a5 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -924,4 +924,22 @@ static inline bool cgroup_task_frozen(struct task_struct *task) #endif /* !CONFIG_CGROUPS */ +#ifdef CONFIG_CGROUP_BPF +static inline void cgroup_bpf_get(struct cgroup *cgrp) +{ + percpu_ref_get(&cgrp->bpf.refcnt); +} + +static inline void cgroup_bpf_put(struct cgroup *cgrp) +{ + percpu_ref_put(&cgrp->bpf.refcnt); +} + +#else /* CONFIG_CGROUP_BPF */ + +static inline void cgroup_bpf_get(struct cgroup *cgrp) {} +static inline void cgroup_bpf_put(struct cgroup *cgrp) {} + +#endif /* CONFIG_CGROUP_BPF */ + #endif /* _LINUX_CGROUP_H */ diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index fcde0f7b25854..d995edbe816dd 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -22,12 +22,21 @@ DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key); EXPORT_SYMBOL(cgroup_bpf_enabled_key); +void cgroup_bpf_offline(struct cgroup *cgrp) +{ + cgroup_get(cgrp); + percpu_ref_kill(&cgrp->bpf.refcnt); +} + /** - * cgroup_bpf_put() - put references of all bpf programs - * @cgrp: the cgroup to modify + * cgroup_bpf_release() - put references of all bpf programs and + * release all cgroup bpf data + * @work: work structure embedded into the cgroup to modify */ -void cgroup_bpf_put(struct cgroup *cgrp) +static void cgroup_bpf_release(struct work_struct *work) { + struct cgroup *cgrp = container_of(work, struct cgroup, + bpf.release_work); enum bpf_cgroup_storage_type stype; unsigned int type; @@ -47,6 +56,22 @@ void cgroup_bpf_put(struct cgroup *cgrp) } bpf_prog_array_free(cgrp->bpf.effective[type]); } + + percpu_ref_exit(&cgrp->bpf.refcnt); + cgroup_put(cgrp); +} + +/** + * cgroup_bpf_release_fn() - callback used to schedule releasing + * of bpf cgroup data + * @ref: percpu ref counter structure + */ +static void cgroup_bpf_release_fn(struct percpu_ref *ref) +{ + struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt); + + INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release); + queue_work(system_wq, &cgrp->bpf.release_work); } /* count number of elements in the list. @@ -167,7 +192,12 @@ int cgroup_bpf_inherit(struct cgroup *cgrp) */ #define NR ARRAY_SIZE(cgrp->bpf.effective) struct bpf_prog_array __rcu *arrays[NR] = {}; - int i; + int ret, i; + + ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0, + GFP_KERNEL); + if (ret) + return ret; for (i = 0; i < NR; i++) INIT_LIST_HEAD(&cgrp->bpf.progs[i]); @@ -183,6 +213,9 @@ int cgroup_bpf_inherit(struct cgroup *cgrp) cleanup: for (i = 0; i < NR; i++) bpf_prog_array_free(arrays[i]); + + percpu_ref_exit(&cgrp->bpf.refcnt); + return -ENOMEM; } diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 217cec4e22c68..ef9cfbfc82a95 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4955,8 +4955,6 @@ static void css_release_work_fn(struct work_struct *work) if (cgrp->kn) RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv, NULL); - - cgroup_bpf_put(cgrp); } mutex_unlock(&cgroup_mutex); @@ -5482,6 +5480,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) cgroup1_check_for_release(parent); + cgroup_bpf_offline(cgrp); + /* put the base reference */ percpu_ref_kill(&cgrp->self.refcnt); @@ -6221,6 +6221,7 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd) * Don't use cgroup_get_live(). */ cgroup_get(sock_cgroup_ptr(skcd)); + cgroup_bpf_get(sock_cgroup_ptr(skcd)); return; } @@ -6232,6 +6233,7 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd) cset = task_css_set(current); if (likely(cgroup_tryget(cset->dfl_cgrp))) { skcd->val = (unsigned long)cset->dfl_cgrp; + cgroup_bpf_get(cset->dfl_cgrp); break; } cpu_relax(); @@ -6242,7 +6244,10 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd) void cgroup_sk_free(struct sock_cgroup_data *skcd) { - cgroup_put(sock_cgroup_ptr(skcd)); + struct cgroup *cgrp = sock_cgroup_ptr(skcd); + + cgroup_bpf_put(cgrp); + cgroup_put(cgrp); } #endif /* CONFIG_SOCK_CGROUP_DATA */