From: Eric Dumazet edumazet@google.com
[ 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: 1da177e4c3f4 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/rose/af_rose.c | 11 +++++++++-- net/rose/rose_route.c | 2 ++ 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index d00a0ef39a56..03a1ee221112 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -194,6 +194,7 @@ 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; } } @@ -594,6 +595,8 @@ 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; @@ -647,6 +650,7 @@ 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; }
diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index 46ae92d70324..5671853bef83 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -616,6 +616,8 @@ 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;