diff options
| author |   Oleksij Rempel <o.rempel@pengutronix.de> | 2018-10-30 09:00:34 +0100 |
|---|---|---|
| committer |   Marc Kleine-Budde <mkl@pengutronix.de> | 2019-09-04 13:29:15 +0200 |
| commit | 24efc6d36d2373468fe5999aad9a4fe843958b4b (patch) | |
| tree | 9707414b13cd29968241fb84c38356528f3adb52 /net/can | |
| parent | can: af_can: remove NULL-ptr checks from users of can_dev_rcv_lists_find() (diff) | |
| download | linux-dev-24efc6d36d2373468fe5999aad9a4fe843958b4b.tar.xz linux-dev-24efc6d36d2373468fe5999aad9a4fe843958b4b.zip | |
can: af_can: use spin_lock_bh() for &net->can.rcvlists_lock
The can_rx_unregister() can be called from NAPI (soft IRQ) context, at least
by j1939 stack. This leads to potential dead lock with &net->can.rcvlists_lock
called from can_rx_register:
===============================================================================
WARNING: inconsistent lock state
4.19.0-20181029-1-g3e67f95ba0d3 #3 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
testj1939/224 [HC0[0]:SC1[1]:HE1:SE0] takes:
1ad0fda3 (&(&net->can.rcvlists_lock)->rlock){+.?.}, at: can_rx_unregister+0x4c/0x1ac
{SOFTIRQ-ON-W} state was registered at:
lock_acquire+0xd0/0x1f4
_raw_spin_lock+0x30/0x40
can_rx_register+0x5c/0x14c
j1939_netdev_start+0xdc/0x1f8
j1939_sk_bind+0x18c/0x1c8
__sys_bind+0x70/0xb0
sys_bind+0x10/0x14
ret_fast_syscall+0x0/0x28
0xbedc9b64
irq event stamp: 2440
hardirqs last enabled at (2440): [<c01302c0>] __local_bh_enable_ip+0xac/0x184
hardirqs last disabled at (2439): [<c0130274>] __local_bh_enable_ip+0x60/0x184
softirqs last enabled at (2412): [<c08b0bf4>] release_sock+0x84/0xa4
softirqs last disabled at (2415): [<c013055c>] irq_exit+0x100/0x1b0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&net->can.rcvlists_lock)->rlock);
<Interrupt>
lock(&(&net->can.rcvlists_lock)->rlock);
*** DEADLOCK ***
2 locks held by testj1939/224:
#0: 168eb13b (rcu_read_lock){....}, at: netif_receive_skb_internal+0x3c/0x350
#1: 168eb13b (rcu_read_lock){....}, at: can_receive+0x88/0x1c0
===============================================================================
To avoid this situation, we should use spin_lock_bh() instead of spin_lock().
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'net/can')
| -rw-r--r-- | net/can/af_can.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/can/af_can.c b/net/can/af_can.c index 25f0d510e1bf..5518a7d9eed9 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -459,7 +459,7 @@ int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id, if (!rcv) return -ENOMEM; - spin_lock(&net->can.rcvlists_lock); + spin_lock_bh(&net->can.rcvlists_lock); dev_rcv_lists = can_dev_rcv_lists_find(net, dev); rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); @@ -478,7 +478,7 @@ int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id, rcv_lists_stats->rcv_entries++; rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max, rcv_lists_stats->rcv_entries); - spin_unlock(&net->can.rcvlists_lock); + spin_unlock_bh(&net->can.rcvlists_lock); return err; } @@ -521,7 +521,7 @@ void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, if (dev && !net_eq(net, dev_net(dev))) return; - spin_lock(&net->can.rcvlists_lock); + spin_lock_bh(&net->can.rcvlists_lock); dev_rcv_lists = can_dev_rcv_lists_find(net, dev); rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); @@ -552,7 +552,7 @@ void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, rcv_lists_stats->rcv_entries--; out: - spin_unlock(&net->can.rcvlists_lock); + spin_unlock_bh(&net->can.rcvlists_lock); /* schedule the receiver item for deletion */ if (rcv) { |