can: bcm/raw/isotp: use per module netdevice notifier

syzbot is reporting hung task at register_netdevice_notifier() [1] and
unregister_netdevice_notifier() [2], for cleanup_net() might perform
time consuming operations while CAN driver's raw/bcm/isotp modules are
calling {register,unregister}_netdevice_notifier() on each socket.

Change raw/bcm/isotp modules to call register_netdevice_notifier() from
module's __init function and call unregister_netdevice_notifier() from
module's __exit function, as with gw/j1939 modules are doing.

Link: https://syzkaller.appspot.com/bug?id=391b9498827788b3cc6830226d4ff5be87107c30
Link: https://syzkaller.appspot.com/bug?id=1724d278c83ca6e6df100a2e320c10d991cf2bce
Link: https://lore.kernel.org/r/54a5f451-05ed-f977-8534-79e7aa2bcc8f@i-love.sakura.ne.jp
Cc: linux-stable <stable@vger.kernel.org>
Reported-by: syzbot <syzbot+355f8edb2ff45d5f95fa@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+0f1827363a305f74996f@syzkaller.appspotmail.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Tested-by: syzbot <syzbot+355f8edb2ff45d5f95fa@syzkaller.appspotmail.com>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 909b9e6..f00176b 100644 (file)
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -125,7 +125,7 @@ struct bcm_sock {
        struct sock sk;
        int bound;
        int ifindex;
-       struct notifier_block notifier;
+       struct list_head notifier;
        struct list_head rx_ops;
        struct list_head tx_ops;
        unsigned long dropped_usr_msgs;
@@ -133,6 +133,10 @@ struct bcm_sock {
        char procname [32]; /* inode number in decimal with \0 */
 };
 
+static LIST_HEAD(bcm_notifier_list);
+static DEFINE_SPINLOCK(bcm_notifier_lock);
+static struct bcm_sock *bcm_busy_notifier;
+
 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
 {
        return (struct bcm_sock *)sk;
@@ -1378,20 +1382,15 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 /*
  * notification handler for netdevice status changes
  */
-static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
-                       void *ptr)
+static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
+                      struct net_device *dev)
 {
-       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-       struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
        struct sock *sk = &bo->sk;
        struct bcm_op *op;
        int notify_enodev = 0;
 
        if (!net_eq(dev_net(dev), sock_net(sk)))
-               return NOTIFY_DONE;
-
-       if (dev->type != ARPHRD_CAN)
-               return NOTIFY_DONE;
+               return;
 
        switch (msg) {
 
@@ -1426,7 +1425,28 @@ static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
                                sk->sk_error_report(sk);
                }
        }
+}
 
+static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
+                       void *ptr)
+{
+       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+       if (dev->type != ARPHRD_CAN)
+               return NOTIFY_DONE;
+       if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+               return NOTIFY_DONE;
+       if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
+               return NOTIFY_DONE;
+
+       spin_lock(&bcm_notifier_lock);
+       list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
+               spin_unlock(&bcm_notifier_lock);
+               bcm_notify(bcm_busy_notifier, msg, dev);
+               spin_lock(&bcm_notifier_lock);
+       }
+       bcm_busy_notifier = NULL;
+       spin_unlock(&bcm_notifier_lock);
        return NOTIFY_DONE;
 }
 
@@ -1446,9 +1466,9 @@ static int bcm_init(struct sock *sk)
        INIT_LIST_HEAD(&bo->rx_ops);
 
        /* set notifier */
-       bo->notifier.notifier_call = bcm_notifier;
-
-       register_netdevice_notifier(&bo->notifier);
+       spin_lock(&bcm_notifier_lock);
+       list_add_tail(&bo->notifier, &bcm_notifier_list);
+       spin_unlock(&bcm_notifier_lock);
 
        return 0;
 }
@@ -1471,7 +1491,14 @@ static int bcm_release(struct socket *sock)
 
        /* remove bcm_ops, timer, rx_unregister(), etc. */
 
-       unregister_netdevice_notifier(&bo->notifier);
+       spin_lock(&bcm_notifier_lock);
+       while (bcm_busy_notifier == bo) {
+               spin_unlock(&bcm_notifier_lock);
+               schedule_timeout_uninterruptible(1);
+               spin_lock(&bcm_notifier_lock);
+       }
+       list_del(&bo->notifier);
+       spin_unlock(&bcm_notifier_lock);
 
        lock_sock(sk);
 
@@ -1692,6 +1719,10 @@ static struct pernet_operations canbcm_pernet_ops __read_mostly = {
        .exit = canbcm_pernet_exit,
 };
 
+static struct notifier_block canbcm_notifier = {
+       .notifier_call = bcm_notifier
+};
+
 static int __init bcm_module_init(void)
 {
        int err;
@@ -1705,12 +1736,14 @@ static int __init bcm_module_init(void)
        }
 
        register_pernet_subsys(&canbcm_pernet_ops);
+       register_netdevice_notifier(&canbcm_notifier);
        return 0;
 }
 
 static void __exit bcm_module_exit(void)
 {
        can_proto_unregister(&bcm_can_proto);
+       unregister_netdevice_notifier(&canbcm_notifier);
        unregister_pernet_subsys(&canbcm_pernet_ops);
 }
 

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 253b244..be6183f 100644 (file)
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -143,10 +143,14 @@ struct isotp_sock {
        u32 force_tx_stmin;
        u32 force_rx_stmin;
        struct tpcon rx, tx;
-       struct notifier_block notifier;
+       struct list_head notifier;
        wait_queue_head_t wait;
 };
 
+static LIST_HEAD(isotp_notifier_list);
+static DEFINE_SPINLOCK(isotp_notifier_lock);
+static struct isotp_sock *isotp_busy_notifier;
+
 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
 {
        return (struct isotp_sock *)sk;
@@ -1013,7 +1017,14 @@ static int isotp_release(struct socket *sock)
        /* wait for complete transmission of current pdu */
        wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
 
-       unregister_netdevice_notifier(&so->notifier);
+       spin_lock(&isotp_notifier_lock);
+       while (isotp_busy_notifier == so) {
+               spin_unlock(&isotp_notifier_lock);
+               schedule_timeout_uninterruptible(1);
+               spin_lock(&isotp_notifier_lock);
+       }
+       list_del(&so->notifier);
+       spin_unlock(&isotp_notifier_lock);
 
        lock_sock(sk);
 
@@ -1317,21 +1328,16 @@ static int isotp_getsockopt(struct socket *sock, int level, int optname,
        return 0;
 }
 
-static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
-                         void *ptr)
+static void isotp_notify(struct isotp_sock *so, unsigned long msg,
+                        struct net_device *dev)
 {
-       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-       struct isotp_sock *so = container_of(nb, struct isotp_sock, notifier);
        struct sock *sk = &so->sk;
 
        if (!net_eq(dev_net(dev), sock_net(sk)))
-               return NOTIFY_DONE;
-
-       if (dev->type != ARPHRD_CAN)
-               return NOTIFY_DONE;
+               return;
 
        if (so->ifindex != dev->ifindex)
-               return NOTIFY_DONE;
+               return;
 
        switch (msg) {
        case NETDEV_UNREGISTER:
@@ -1357,7 +1363,28 @@ static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
                        sk->sk_error_report(sk);
                break;
        }
+}
 
+static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
+                         void *ptr)
+{
+       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+       if (dev->type != ARPHRD_CAN)
+               return NOTIFY_DONE;
+       if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+               return NOTIFY_DONE;
+       if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
+               return NOTIFY_DONE;
+
+       spin_lock(&isotp_notifier_lock);
+       list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
+               spin_unlock(&isotp_notifier_lock);
+               isotp_notify(isotp_busy_notifier, msg, dev);
+               spin_lock(&isotp_notifier_lock);
+       }
+       isotp_busy_notifier = NULL;
+       spin_unlock(&isotp_notifier_lock);
        return NOTIFY_DONE;
 }
 
@@ -1394,8 +1421,9 @@ static int isotp_init(struct sock *sk)
 
        init_waitqueue_head(&so->wait);
 
-       so->notifier.notifier_call = isotp_notifier;
-       register_netdevice_notifier(&so->notifier);
+       spin_lock(&isotp_notifier_lock);
+       list_add_tail(&so->notifier, &isotp_notifier_list);
+       spin_unlock(&isotp_notifier_lock);
 
        return 0;
 }
@@ -1442,6 +1470,10 @@ static const struct can_proto isotp_can_proto = {
        .prot = &isotp_proto,
 };
 
+static struct notifier_block canisotp_notifier = {
+       .notifier_call = isotp_notifier
+};
+
 static __init int isotp_module_init(void)
 {
        int err;
@@ -1451,6 +1483,8 @@ static __init int isotp_module_init(void)
        err = can_proto_register(&isotp_can_proto);
        if (err < 0)
                pr_err("can: registration of isotp protocol failed\n");
+       else
+               register_netdevice_notifier(&canisotp_notifier);
 
        return err;
 }
@@ -1458,6 +1492,7 @@ static __init int isotp_module_init(void)
 static __exit void isotp_module_exit(void)
 {
        can_proto_unregister(&isotp_can_proto);
+       unregister_netdevice_notifier(&canisotp_notifier);
 }
 
 module_init(isotp_module_init);

diff --git a/net/can/raw.c b/net/can/raw.c
index 139d947..ac96fc2 100644 (file)
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -83,7 +83,7 @@ struct raw_sock {
        struct sock sk;
        int bound;
        int ifindex;
-       struct notifier_block notifier;
+       struct list_head notifier;
        int loopback;
        int recv_own_msgs;
        int fd_frames;
@@ -95,6 +95,10 @@ struct raw_sock {
        struct uniqframe __percpu *uniq;
 };
 
+static LIST_HEAD(raw_notifier_list);
+static DEFINE_SPINLOCK(raw_notifier_lock);
+static struct raw_sock *raw_busy_notifier;
+
 /* Return pointer to store the extra msg flags for raw_recvmsg().
  * We use the space of one unsigned int beyond the 'struct sockaddr_can'
  * in skb->cb.
@@ -263,21 +267,16 @@ static int raw_enable_allfilters(struct net *net, struct net_device *dev,
        return err;
 }
 
-static int raw_notifier(struct notifier_block *nb,
-                       unsigned long msg, void *ptr)
+static void raw_notify(struct raw_sock *ro, unsigned long msg,
+                      struct net_device *dev)
 {
-       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-       struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
        struct sock *sk = &ro->sk;
 
        if (!net_eq(dev_net(dev), sock_net(sk)))
-               return NOTIFY_DONE;
-
-       if (dev->type != ARPHRD_CAN)
-               return NOTIFY_DONE;
+               return;
 
        if (ro->ifindex != dev->ifindex)
-               return NOTIFY_DONE;
+               return;
 
        switch (msg) {
        case NETDEV_UNREGISTER:
@@ -305,7 +304,28 @@ static int raw_notifier(struct notifier_block *nb,
                        sk->sk_error_report(sk);
                break;
        }
+}
+
+static int raw_notifier(struct notifier_block *nb, unsigned long msg,
+                       void *ptr)
+{
+       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+       if (dev->type != ARPHRD_CAN)
+               return NOTIFY_DONE;
+       if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+               return NOTIFY_DONE;
+       if (unlikely(raw_busy_notifier)) /* Check for reentrant bug. */
+               return NOTIFY_DONE;
 
+       spin_lock(&raw_notifier_lock);
+       list_for_each_entry(raw_busy_notifier, &raw_notifier_list, notifier) {
+               spin_unlock(&raw_notifier_lock);
+               raw_notify(raw_busy_notifier, msg, dev);
+               spin_lock(&raw_notifier_lock);
+       }
+       raw_busy_notifier = NULL;
+       spin_unlock(&raw_notifier_lock);
        return NOTIFY_DONE;
 }
 
@@ -334,9 +354,9 @@ static int raw_init(struct sock *sk)
                return -ENOMEM;
 
        /* set notifier */
-       ro->notifier.notifier_call = raw_notifier;
-
-       register_netdevice_notifier(&ro->notifier);
+       spin_lock(&raw_notifier_lock);
+       list_add_tail(&ro->notifier, &raw_notifier_list);
+       spin_unlock(&raw_notifier_lock);
 
        return 0;
 }
@@ -351,7 +371,14 @@ static int raw_release(struct socket *sock)
 
        ro = raw_sk(sk);
 
-       unregister_netdevice_notifier(&ro->notifier);
+       spin_lock(&raw_notifier_lock);
+       while (raw_busy_notifier == ro) {
+               spin_unlock(&raw_notifier_lock);
+               schedule_timeout_uninterruptible(1);
+               spin_lock(&raw_notifier_lock);
+       }
+       list_del(&ro->notifier);
+       spin_unlock(&raw_notifier_lock);
 
        lock_sock(sk);
 
@@ -889,6 +916,10 @@ static const struct can_proto raw_can_proto = {
        .prot       = &raw_proto,
 };
 
+static struct notifier_block canraw_notifier = {
+       .notifier_call = raw_notifier
+};
+
 static __init int raw_module_init(void)
 {
        int err;
@@ -898,6 +929,8 @@ static __init int raw_module_init(void)
        err = can_proto_register(&raw_can_proto);
        if (err < 0)
                pr_err("can: registration of raw protocol failed\n");
+       else
+               register_netdevice_notifier(&canraw_notifier);
 
        return err;
 }
@@ -905,6 +938,7 @@ static __init int raw_module_init(void)
 static __exit void raw_module_exit(void)
 {
        can_proto_unregister(&raw_can_proto);
+       unregister_netdevice_notifier(&canraw_notifier);
 }
 
 module_init(raw_module_init);