From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit 5aa2820177af650293b2f9f1873c1f6f8e4ad7a4 ]
hsr_forward_skb() a skb and keeps information in an on-stack hsr_frame_info. hsr_get_node() assigns hsr_frame_info::node_src which is from a RCU list. This pointer is used later in hsr_forward_do(). I don't see a reason why this pointer can't vanish midway since there is no guarantee that hsr_forward_skb() is invoked from an RCU read section.
Use rcu_read_lock() to protect hsr_frame_info::node_src from its assignment until it is no longer used.
Fixes: f266a683a4804 ("net/hsr: Better frame dispatch") Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/hsr/hsr_forward.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c index 3e58d310b4d4..a8befa35841e 100644 --- a/net/hsr/hsr_forward.c +++ b/net/hsr/hsr_forward.c @@ -614,11 +614,13 @@ void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port) { struct hsr_frame_info frame;
+ rcu_read_lock(); if (fill_frame_info(&frame, skb, port) < 0) goto out_drop;
hsr_register_frame_in(frame.node_src, port, frame.sequence_nr); hsr_forward_do(&frame); + rcu_read_unlock(); /* Gets called for ingress frames as well as egress from master port. * So check and increment stats for master port only here. */ @@ -633,6 +635,7 @@ void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port) return;
out_drop: + rcu_read_unlock(); port->dev->stats.tx_dropped++; kfree_skb(skb); }