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hsr: Add a rcu-read lock to hsr_forward_skb().

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[ Upstream commit 5aa2820177 ]

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: f266a683a4 ("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>
This commit is contained in:
Sebastian Andrzej Siewior 2022-11-29 17:48:09 +01:00 • committed by Greg Kroah-Hartman
commit 38d13a2a9e
1 changed files with 3 additions and 0 deletions
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3
net/hsr/hsr_forward.c
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@ -545,11 +545,13 @@ 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.
*/
@ -564,6 +566,7 @@ 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);
}