The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 8d0caedb759683041d9db82069937525999ada53 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Sat, 5 Jun 2021 19:26:35 +0900
Subject: [PATCH] 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 [1]
Link: https://syzkaller.appspot.com/bug?id=1724d278c83ca6e6df100a2e320c10d991cf2bce [2]
Link: https://lore.kernel.org/r/54a5f451-05ed-f977-8534-79e7aa2bcc8f@xxxxxxxxxxxxxxxxxxx
Cc: linux-stable <stable@xxxxxxxxxxxxxxx>
Reported-by: syzbot <syzbot+355f8edb2ff45d5f95fa@xxxxxxxxxxxxxxxxxxxxxxxxx>
Reported-by: syzbot <syzbot+0f1827363a305f74996f@xxxxxxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Tested-by: syzbot <syzbot+355f8edb2ff45d5f95fa@xxxxxxxxxxxxxxxxxxxxxxxxx>
Tested-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 909b9e684e04..f00176b2a6c3 100644
--- 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 253b24417c8e..be6183f8ca11 100644
--- 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 139d9471ddcf..ac96fc210025 100644
--- 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);
