Merge tag 'linux-can-fixes-for-4.14-20171019' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2017-10-19

this is a pull request of 11 patches for the upcoming 4.14 release.

There are 6 patches by ZHU Yi for the flexcan driver, that work around
the CAN error handling state transition problems found in various
incarnations of the flexcan IP core.

The patch by Colin Ian King fixes a potential NULL pointer deref in the
CAN broad cast manager (bcm). One patch by me replaces a direct deref of a RCU
protected pointer by rcu_access_pointer. My second patch adds missing
OOM error handling in af_can. A patch by Stefan Mätje for the esd_usb2
driver fixes the dlc in received RTR frames. And the last patch is by
Wolfgang Grandegger, it fixes a busy loop in the gs_usb driver in case
it runs out of TX contexts.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 19 insertions, 6 deletions

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 88edac0f3e36..ecd5c703d11e 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -78,7 +78,7 @@ MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
 static struct kmem_cache *rcv_cache __read_mostly;
 
 /* table of registered CAN protocols */
-static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
+static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
 static DEFINE_MUTEX(proto_tab_lock);
 
 static atomic_t skbcounter = ATOMIC_INIT(0);
@@ -788,7 +788,7 @@ int can_proto_register(const struct can_proto *cp)
 
 	mutex_lock(&proto_tab_lock);
 
-	if (proto_tab[proto]) {
+	if (rcu_access_pointer(proto_tab[proto])) {
 		pr_err("can: protocol %d already registered\n", proto);
 		err = -EBUSY;
 	} else
@@ -812,7 +812,7 @@ void can_proto_unregister(const struct can_proto *cp)
 	int proto = cp->protocol;
 
 	mutex_lock(&proto_tab_lock);
-	BUG_ON(proto_tab[proto] != cp);
+	BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
 	RCU_INIT_POINTER(proto_tab[proto], NULL);
 	mutex_unlock(&proto_tab_lock);
 
@@ -875,9 +875,14 @@ static int can_pernet_init(struct net *net)
 	spin_lock_init(&net->can.can_rcvlists_lock);
 	net->can.can_rx_alldev_list =
 		kzalloc(sizeof(struct dev_rcv_lists), GFP_KERNEL);
-
+	if (!net->can.can_rx_alldev_list)
+		goto out;
 	net->can.can_stats = kzalloc(sizeof(struct s_stats), GFP_KERNEL);
+	if (!net->can.can_stats)
+		goto out_free_alldev_list;
 	net->can.can_pstats = kzalloc(sizeof(struct s_pstats), GFP_KERNEL);
+	if (!net->can.can_pstats)
+		goto out_free_can_stats;
 
 	if (IS_ENABLED(CONFIG_PROC_FS)) {
 		/* the statistics are updated every second (timer triggered) */
@@ -892,6 +897,13 @@ static int can_pernet_init(struct net *net)
 	}
 
 	return 0;
+
+ out_free_can_stats:
+	kfree(net->can.can_stats);
+ out_free_alldev_list:
+	kfree(net->can.can_rx_alldev_list);
+ out:
+	return -ENOMEM;
 }
 
 static void can_pernet_exit(struct net *net)
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 47a8748d953a..13690334efa3 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1493,13 +1493,14 @@ static int bcm_init(struct sock *sk)
 static int bcm_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
-	struct net *net = sock_net(sk);
+	struct net *net;
 	struct bcm_sock *bo;
 	struct bcm_op *op, *next;
 
-	if (sk == NULL)
+	if (!sk)
 		return 0;
 
+	net = sock_net(sk);
 	bo = bcm_sk(sk);
 
 	/* remove bcm_ops, timer, rx_unregister(), etc. */