From: Stanislav Kinsburskiy <skinsbur...@virtuozzo.com>
This helpers will be used later to initialize per-container connector.
Signed-off-by: Stanislav Kinsburskiy <skinsbur...@virtuozzo.com>
Reviewed-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
+++
connector: avoid RCU read-side critical section in cn_init_ve()
First, netlink_kernel_create() cannot be called under rcu_read_lock()
(inside ve_net_lock()) because it sleeps.
Second, cn_init_ve() is a hook called on VE creation, VE creation is
done in a single thread, all hooks are called under a lock =>
ve cannot be destroyed during start hook execution => rcu_read_lock() is
not needed at all here.
mFixes: e7b9a7d5ce79 ("connector: per-ve init and fini helpers
introduced")
https://jira.sw.ru/browse/PSBM-93640
Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com>
(cherry picked from vz8 commit 010b6038d20f9e33753584bf53bf60954781233b)
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
---
drivers/connector/connector.c | 54 +++++++++++++++++++++++++++++------
1 file changed, 45 insertions(+), 9 deletions(-)
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index a4348d68698b..8d184588d53e 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -249,41 +249,77 @@ static int __maybe_unused cn_proc_show(struct seq_file
*m, void *v)
return 0;
}
-static int cn_init(void)
+static int cn_init_ve(struct ve_struct *ve)
{
struct cn_dev *dev = get_cdev(get_ve0());
struct netlink_kernel_cfg cfg = {
.groups = CN_NETLINK_USERS + 0xf,
.input = cn_rx_skb,
};
+ struct net *net;
+ int err;
+
+ ve->cn = kzalloc(sizeof(*ve->cn), GFP_KERNEL);
+ if (!ve->cn)
+ return -ENOMEM;
- dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, &cfg);
+ /*
+ * This is a hook, hooks are called under a single lock, so ve_ns will
+ * not disappear, so rcu_read_lock()/unlock is not needed here.
+ */
+ net = rcu_dereference_check(ve->ve_ns, 1)->net_ns;
+
+ err = -EIO;
+ dev->nls = netlink_kernel_create(net, NETLINK_CONNECTOR, &cfg);
if (!dev->nls)
- return -EIO;
+ goto net_unlock;
+ err = -EINVAL;
dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
if (!dev->cbdev) {
netlink_kernel_release(dev->nls);
- return -EINVAL;
+ goto net_unlock;
}
cn_already_initialized = 1;
- proc_create_single("connector", S_IRUGO, init_net.proc_net,
cn_proc_show);
+ proc_create_single("connector", S_IRUGO, net->proc_net, cn_proc_show);
+ err = 0;
- return 0;
+net_unlock:
+ return err;
}
-static void cn_fini(void)
+static void cn_fini_ve(struct ve_struct *ve)
{
- struct cn_dev *dev = get_cdev(get_ve0());
+ struct cn_dev *dev = get_cdev(ve);
+ struct net *net;
cn_already_initialized = 0;
- remove_proc_entry("connector", init_net.proc_net);
+ /*
+ * This is a hook called on ve stop, ve->ve_ns will be destroyed
+ * later in the same thread, parallel ve stop is impossible,
+ * so rcu_read_lock()/unlock is not needed here.
+ */
+ net = rcu_dereference_check(ve->ve_ns, 1)->net_ns;
+ remove_proc_entry("connector", net->proc_net);
cn_queue_free_dev(dev->cbdev);
netlink_kernel_release(dev->nls);
+
+ kfree(ve->cn);
+ ve->cn = NULL;
+}
+
+static int cn_init(void)
+{
+ return cn_init_ve(get_ve0());
+}
+
+static void cn_fini(void)
+{
+ return cn_fini_ve(get_ve0());
}
subsys_initcall(cn_init);
--
2.31.1
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