summaryrefslogtreecommitdiffstats
path: root/net/can/af_can.c
diff options
context:
space:
mode:
authorOleksij Rempel <o.rempel@pengutronix.de>2018-10-30 09:00:34 +0100
committerMarc Kleine-Budde <mkl@pengutronix.de>2019-09-04 13:29:15 +0200
commit24efc6d36d2373468fe5999aad9a4fe843958b4b (patch)
tree9707414b13cd29968241fb84c38356528f3adb52 /net/can/af_can.c
parentcan: af_can: remove NULL-ptr checks from users of can_dev_rcv_lists_find() (diff)
downloadlinux-24efc6d36d2373468fe5999aad9a4fe843958b4b.tar.xz
linux-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/af_can.c')
-rw-r--r--net/can/af_can.c8
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) {