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net: rose: fix netdev reference changes 

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: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Bernard Pidoux <f6bvp@free.fr>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Bernard Pidoux <f6bvp@free.fr>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2022-07-29 09:12:32 +00:00 committed by Jakub Kicinski
parent 9936e07eaf
commit 931027820e
2 changed files with 11 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
net/rose/af_rose.c
View File

@ -192,6 +192,7 @@ 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;
}
}
@ -592,6 +593,8 @@ 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;
@ -645,6 +648,7 @@ static int rose_release(struct socket *sock)
break;
}
dev_put(rose->device);
sock->sk = NULL;
release_sock(sk);
sock_put(sk);
@ -721,7 +725,6 @@ 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;
@ -778,9 +781,12 @@ 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;
}
@ -788,6 +794,7 @@ 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;
}

2
net/rose/rose_route.c
View File

@ -615,6 +615,8 @@ 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;