Re: [PATCH v0 3/5] cgroup: Protect access to task_cls_classid() when built as module
From: Li Zefan <hidden>
Date: 2012-08-17 07:35:27
Also in:
netdev
+#if IS_ENABLED(CONFIG_NET_CLS_CGROUP) +extern struct static_key cgroup_cls_enabled; +#define clscg_enabled static_key_false(&cgroup_cls_enabled) +#endif +
If it's built-in, clscg_enabled is always true (after we call cgroup_subsys_init at boot), so we don't need jump label at all.
quoted hunk
extern void sock_update_classid(struct sock *sk); #if IS_BUILTIN(CONFIG_NET_CLS_CGROUP)@@ -52,7 +58,7 @@ static inline u32 task_cls_classid(struct task_struct *p) int id; u32 classid = 0; - if (in_interrupt()) + if (!clscg_enabled || in_interrupt()) return 0; rcu_read_lock();diff --git a/net/core/sock.c b/net/core/sock.c index 8f67ced..8d3a400 100644 --- a/net/core/sock.c +++ b/net/core/sock.c@@ -327,6 +327,11 @@ int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) EXPORT_SYMBOL(__sk_backlog_rcv); #if defined(CONFIG_CGROUPS) +#if IS_ENABLED(CONFIG_NET_CLS_CGROUP) +struct static_key cgroup_cls_enabled = STATIC_KEY_INIT_FALSE; +EXPORT_SYMBOL_GPL(cgroup_cls_enabled); +#endif + #if !defined(CONFIG_NET_CLS_CGROUP) int net_cls_subsys_id = -1; EXPORT_SYMBOL_GPL(net_cls_subsys_id);diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c index 7743ea8..f40086b 100644 --- a/net/sched/cls_cgroup.c +++ b/net/sched/cls_cgroup.c@@ -44,12 +44,17 @@ static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp) if (cgrp->parent) cs->classid = cgrp_cls_state(cgrp->parent)->classid; + else if (!clscg_enabled) + static_key_slow_inc(&cgroup_cls_enabled);
It's not necessary to check if !clsg_enabled.
return &cs->css;
}
static void cgrp_destroy(struct cgroup *cgrp)
{
+ if (!cgrp->parent && clscg_enabled)
+ static_key_slow_dec(&cgroup_cls_enabled);
+ditto.
kfree(cgrp_cls_state(cgrp)); }