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Commit d3b29226 authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman
Browse files

net: rose: fix netdev reference changes 



[ Upstream commit 931027820e4dafabc78aff82af59f8c1c4bd3128 ]

Bernard reported that trying to unload rose module would lead
to infamous messages:

unregistered_netdevice: waiting for rose0 to become free. Usage count = xx

This patch solves the issue, by making sure each socket referring to
a netdevice holds a reference count on it, and properly releases it
in rose_release().

rose_dev_first() is also fixed to take a device reference
before leaving the rcu_read_locked section.

Following patch will add ref_tracker annotations to ease
future bug hunting.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by: default avatarBernard Pidoux <f6bvp@free.fr>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Tested-by: default avatarBernard Pidoux <f6bvp@free.fr>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 34b88491

net/rose/af_rose.c

+9 −2
Original line number Diff line number Diff line
@@ -169,6 +169,7 @@ static void rose_kill_by_device(struct net_device *dev) 
			rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0);

			if (rose->neighbour)

				rose->neighbour->use--;

			dev_put(rose->device);

			rose->device = NULL;

		}

	}
@@ -569,6 +570,8 @@ static struct sock *rose_make_new(struct sock *osk) 
	rose->idle	= orose->idle;

	rose->defer	= orose->defer;

	rose->device	= orose->device;

	if (rose->device)

		dev_hold(rose->device);

	rose->qbitincl	= orose->qbitincl;



	return sk;
@@ -622,6 +625,7 @@ static int rose_release(struct socket *sock) 
		break;

	}



	dev_put(rose->device);

	sock->sk = NULL;

	release_sock(sk);

	sock_put(sk);
@@ -698,7 +702,6 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le 
	struct rose_sock *rose = rose_sk(sk);

	struct sockaddr_rose *addr = (struct sockaddr_rose *)uaddr;

	unsigned char cause, diagnostic;

	struct net_device *dev;

	ax25_uid_assoc *user;

	int n, err = 0;
@@ -755,9 +758,12 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le 
	}



	if (sock_flag(sk, SOCK_ZAPPED)) {	/* Must bind first - autobinding in this may or may not work */

		struct net_device *dev;



		sock_reset_flag(sk, SOCK_ZAPPED);



		if ((dev = rose_dev_first()) == NULL) {

		dev = rose_dev_first();

		if (!dev) {

			err = -ENETUNREACH;

			goto out_release;

		}
@@ -765,6 +771,7 @@ static int rose_connect(struct socket *sock, struct sockaddr *uaddr, int addr_le 
		user = ax25_findbyuid(current_euid());

		if (!user) {

			err = -EINVAL;

			dev_put(dev);

			goto out_release;

		}

net/rose/rose_route.c

+2 −0
Original line number Diff line number Diff line
@@ -613,6 +613,8 @@ struct net_device *rose_dev_first(void) 
			if (first == NULL || strncmp(dev->name, first->name, 3) < 0)

				first = dev;

	}

	if (first)

		dev_hold(first);

	rcu_read_unlock();



	return first;