[PATCH 6.12 057/244] can: statistics: add missing atomic access in hot path

Greg Kroah-Hartman
2026-03-31T16:48:32Z

From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit 46eee1661aa9b49966e6c43d07126fe408edda57 ]

Commit 80b5f90158d1 ("can: statistics: use atomic access in hot path")
fixed a KCSAN issue in can_receive() but missed to convert the 'matches'
variable used in can_rcv_filter().

Fixes: 80b5f90158d1 ("can: statistics: use atomic access in hot path")
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20260318173413.28235-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/can/af_can.c | 4 ++--
net/can/af_can.h | 2 +-
net/can/proc.c | 3 ++-
3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 65230e81fa08c..c86cbb3ed9c54 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -467,7 +467,7 @@ int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,

rcv->can_id = can_id;
rcv->mask = mask;
- rcv->matches = 0;
+ atomic_long_set(&rcv->matches, 0);
rcv->func = func;
rcv->data = data;
rcv->ident = ident;
@@ -571,7 +571,7 @@ EXPORT_SYMBOL(can_rx_unregister);
static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
{
rcv->func(skb, rcv->data);
- rcv->matches++;
+ atomic_long_inc(&rcv->matches);
}

static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
diff --git a/net/can/af_can.h b/net/can/af_can.h
index 22f3352c77fec..87887014f5628 100644
--- a/net/can/af_can.h
+++ b/net/can/af_can.h
@@ -52,7 +52,7 @@ struct receiver {
struct hlist_node list;
canid_t can_id;
canid_t mask;
- unsigned long matches;
+ atomic_long_t matches;
void (*func)(struct sk_buff *skb, void *data);
void *data;
char *ident;
diff --git a/net/can/proc.c b/net/can/proc.c
index 25fdf060e30d0..2f78ea8ac30b0 100644
--- a/net/can/proc.c
+++ b/net/can/proc.c
@@ -196,7 +196,8 @@ static void can_print_rcvlist(struct seq_file *m, struct hlist_head *rx_list,
" %-5s %03x %08x %pK %pK %8ld %s\n";

seq_printf(m, fmt, DNAME(dev), r->can_id, r->mask,
- r->func, r->data, r->matches, r->ident);
+ r->func, r->data, atomic_long_read(&r->matches),
+ r->ident);
}
}

--
2.51.0