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Commit ed5d7788 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

netlink: Do not schedule work from sk_destruct 



It is wrong to schedule a work from sk_destruct using the socket
as the memory reserve because the socket will be freed immediately
after the return from sk_destruct.

Instead we should do the deferral prior to sk_free.

This patch does just that.

Fixes: 707693c8 ("netlink: Call cb->done from a worker thread")
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Tested-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ffe3bb85

net/netlink/af_netlink.c

+15 −17
Original line number Diff line number Diff line
@@ -322,11 +322,13 @@ static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) 
	sk_mem_charge(sk, skb->truesize);

}



static void __netlink_sock_destruct(struct sock *sk)

static void netlink_sock_destruct(struct sock *sk)

{

	struct netlink_sock *nlk = nlk_sk(sk);



	if (nlk->cb_running) {

		if (nlk->cb.done)

			nlk->cb.done(&nlk->cb);

		module_put(nlk->cb.module);

		kfree_skb(nlk->cb.skb);

	}
@@ -348,21 +350,7 @@ static void netlink_sock_destruct_work(struct work_struct *work) 
	struct netlink_sock *nlk = container_of(work, struct netlink_sock,

						work);



	nlk->cb.done(&nlk->cb);

	__netlink_sock_destruct(&nlk->sk);

}



static void netlink_sock_destruct(struct sock *sk)

{

	struct netlink_sock *nlk = nlk_sk(sk);



	if (nlk->cb_running && nlk->cb.done) {

		INIT_WORK(&nlk->work, netlink_sock_destruct_work);

		schedule_work(&nlk->work);

		return;

	}



	__netlink_sock_destruct(sk);

	sk_free(&nlk->sk);

}



/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
@@ -667,8 +655,18 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol, 
static void deferred_put_nlk_sk(struct rcu_head *head)

{

	struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);

	struct sock *sk = &nlk->sk;



	if (!atomic_dec_and_test(&sk->sk_refcnt))

		return;



	if (nlk->cb_running && nlk->cb.done) {

		INIT_WORK(&nlk->work, netlink_sock_destruct_work);

		schedule_work(&nlk->work);

		return;

	}



	sock_put(&nlk->sk);

	sk_free(sk);

}



static int netlink_release(struct socket *sock)