Got kmemleak errors with the following ltp can_filter testcase:
for ((i=1; i<=100; i++))
do
./can_filter &
sleep 0.1
done
==============================================================
[<00000000db4a4943>] can_rx_register+0x147/0x360 [can]
[<00000000a289549d>] raw_setsockopt+0x5ef/0x853 [can_raw]
[<000000006d3d9ebd>] __sys_setsockopt+0x173/0x2c0
[<00000000407dbfec>] __x64_sys_setsockopt+0x61/0x70
[<00000000fd468496>] do_syscall_64+0x33/0x40
[<00000000b7e47d51>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
It's a bug in the concurrent scenario of unregister_netdevice_many()
and raw_release() as following:
cpu0 cpu1
unregister_netdevice_many(can_dev)
unlist_netdevice(can_dev) // dev_get_by_index() return NULL after this
net_set_todo(can_dev)
raw_release(can_socket)
dev = dev_get_by_index(, ro->ifindex); // dev == NULL
if (dev) { // receivers in dev_rcv_lists not free because dev is NULL
raw_disable_allfilters(, dev, );
dev_put(dev);
}
...
ro->bound = 0;
...
call_netdevice_notifiers(NETDEV_UNREGISTER, )
raw_notify(, NETDEV_UNREGISTER, )
if (ro->bound) // invalid because ro->bound has been set 0
raw_disable_allfilters(, dev, ); // receivers in dev_rcv_lists will never be freed
Add a net_device pointer member in struct raw_sock to record bound can_dev,
and use rtnl_lock to serialize raw_socket members between raw_bind(), raw_release(),
raw_setsockopt() and raw_notify(). Use ro->dev to decide whether to free receivers in
dev_rcv_lists.
Fixes: 8d0caedb7596 ("can: bcm/raw/isotp: use per module netdevice notifier")
Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
Reviewed-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
v3:
- Remove unnecessary coding style changes.
- Add Reviewed-by and Acked-by tags.
v2:
- Do not hold idev anyway firstly.
---
net/can/raw.c | 57 ++++++++++++++++++++++-----------------------------
1 file changed, 24 insertions(+), 33 deletions(-)
diff --git a/net/can/raw.c b/net/can/raw.c
index 15c79b079184..2302e4882967 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -84,6 +84,7 @@ struct raw_sock {
struct sock sk;
int bound;
int ifindex;
+ struct net_device *dev;
struct list_head notifier;
int loopback;
int recv_own_msgs;
@@ -277,7 +278,7 @@ static void raw_notify(struct raw_sock *ro, unsigned long msg,
if (!net_eq(dev_net(dev), sock_net(sk)))
return;
- if (ro->ifindex != dev->ifindex)
+ if (ro->dev != dev)
return;
switch (msg) {
@@ -292,6 +293,7 @@ static void raw_notify(struct raw_sock *ro, unsigned long msg,
ro->ifindex = 0;
ro->bound = 0;
+ ro->dev = NULL;
ro->count = 0;
release_sock(sk);
@@ -337,6 +339,7 @@ static int raw_init(struct sock *sk)
ro->bound = 0;
ro->ifindex = 0;
+ ro->dev = NULL;
/* set default filter to single entry dfilter */
ro->dfilter.can_id = 0;
@@ -385,19 +388,13 @@ static int raw_release(struct socket *sock)
lock_sock(sk);
+ rtnl_lock();
/* remove current filters & unregister */
if (ro->bound) {
- if (ro->ifindex) {
- struct net_device *dev;
-
- dev = dev_get_by_index(sock_net(sk), ro->ifindex);
- if (dev) {
- raw_disable_allfilters(dev_net(dev), dev, sk);
- dev_put(dev);
- }
- } else {
+ if (ro->dev)
+ raw_disable_allfilters(dev_net(ro->dev), ro->dev, sk);
+ else
raw_disable_allfilters(sock_net(sk), NULL, sk);
- }
}
if (ro->count > 1)
@@ -405,8 +402,10 @@ static int raw_release(struct socket *sock)
ro->ifindex = 0;
ro->bound = 0;
+ ro->dev = NULL;
ro->count = 0;
free_percpu(ro->uniq);
+ rtnl_unlock();
sock_orphan(sk);
sock->sk = NULL;
@@ -422,6 +421,7 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
struct sock *sk = sock->sk;
struct raw_sock *ro = raw_sk(sk);
+ struct net_device *dev = NULL;
int ifindex;
int err = 0;
int notify_enetdown = 0;
@@ -431,14 +431,13 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
if (addr->can_family != AF_CAN)
return -EINVAL;
+ rtnl_lock();
lock_sock(sk);
if (ro->bound && addr->can_ifindex == ro->ifindex)
goto out;
if (addr->can_ifindex) {
- struct net_device *dev;
-
dev = dev_get_by_index(sock_net(sk), addr->can_ifindex);
if (!dev) {
err = -ENODEV;
@@ -467,26 +466,20 @@ static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
if (!err) {
if (ro->bound) {
/* unregister old filters */
- if (ro->ifindex) {
- struct net_device *dev;
-
- dev = dev_get_by_index(sock_net(sk),
- ro->ifindex);
- if (dev) {
- raw_disable_allfilters(dev_net(dev),
- dev, sk);
- dev_put(dev);
- }
- } else {
+ if (ro->dev)
+ raw_disable_allfilters(dev_net(ro->dev),
+ ro->dev, sk);
+ else
raw_disable_allfilters(sock_net(sk), NULL, sk);
- }
}
ro->ifindex = ifindex;
ro->bound = 1;
+ ro->dev = dev;
}
out:
release_sock(sk);
+ rtnl_unlock();
if (notify_enetdown) {
sk->sk_err = ENETDOWN;
@@ -553,9 +546,9 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
rtnl_lock();
lock_sock(sk);
- if (ro->bound && ro->ifindex) {
- dev = dev_get_by_index(sock_net(sk), ro->ifindex);
- if (!dev) {
+ dev = ro->dev;
+ if (ro->bound && dev) {
+ if (dev->reg_state != NETREG_REGISTERED) {
if (count > 1)
kfree(filter);
err = -ENODEV;
@@ -596,7 +589,6 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
ro->count = count;
out_fil:
- dev_put(dev);
release_sock(sk);
rtnl_unlock();
@@ -614,9 +606,9 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
rtnl_lock();
lock_sock(sk);
- if (ro->bound && ro->ifindex) {
- dev = dev_get_by_index(sock_net(sk), ro->ifindex);
- if (!dev) {
+ dev = ro->dev;
+ if (ro->bound && dev) {
+ if (dev->reg_state != NETREG_REGISTERED) {
err = -ENODEV;
goto out_err;
}
@@ -640,7 +632,6 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
ro->err_mask = err_mask;
out_err:
- dev_put(dev);
release_sock(sk);
rtnl_unlock();
--
2.25.1
