we free css_set when refcnt became 0 immediately(except cgroup_attach_task()).
I will destroy the data which read side maybe still access it.
this patch use call_rcu() to defer free css_set
Signed-off-by: Lai Jiangshan <[EMAIL PROTECTED]>
---
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 1164963..22901ff 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -178,6 +178,8 @@ struct css_set {
*/
struct list_head cg_links;
+ struct rcu_head rcu;
+
/*
* Set of subsystem states, one for each subsystem. This array
* is immutable after creation apart from the init_css_set
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 358e775..ddc10ac 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -252,6 +252,11 @@ static void unlink_css_set(struct css_set *cg)
}
}
+static void rcu_free_css_set(struct rcu_head *head)
+{
+ kfree(container_of(head, struct css_set, rcu));
+}
+
static void __put_css_set(struct css_set *cg, int taskexit)
{
int i;
@@ -281,7 +286,7 @@ static void __put_css_set(struct css_set *cg, int taskexit)
}
}
rcu_read_unlock();
- kfree(cg);
+ call_rcu(&cg->rcu, rcu_free_css_set);
}
/*
@@ -1267,7 +1277,6 @@ int cgroup_attach_task(struct cgroup *cgrp, struct
task_struct *tsk)
ss->attach(ss, cgrp, oldcgrp, tsk);
}
set_bit(CGRP_RELEASABLE, &oldcgrp->flags);
- synchronize_rcu();
put_css_set(cg);
return 0;
}
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