This is a note to let you know that I've just added the patch titled
neighbour: fix data-races around n->output
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
neighbour-fix-data-races-around-n-output.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0f65c7bd482f8d2f4e15fd008e92efa287fda59c
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Thu Sep 21 09:27:13 2023 +0000
neighbour: fix data-races around n->output
[ Upstream commit 5baa0433a15eadd729625004c37463acb982eca7 ]
n->output field can be read locklessly, while a writer
might change the pointer concurrently.
Add missing annotations to prevent load-store tearing.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index f6a8ecc6b1fa7..ccc4a0f8b4ad8 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -541,7 +541,7 @@ static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
READ_ONCE(hh->hh_len))
return neigh_hh_output(hh, skb);
- return n->output(n, skb);
+ return READ_ONCE(n->output)(n, skb);
}
static inline struct neighbour *
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 442198cb83909..01d690d9fe5f8 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -294,7 +294,7 @@ int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_
/* tell br_dev_xmit to continue with forwarding */
nf_bridge->bridged_dnat = 1;
/* FIXME Need to refragment */
- ret = neigh->output(neigh, skb);
+ ret = READ_ONCE(neigh->output)(neigh, skb);
}
neigh_release(neigh);
return ret;
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index bafd72e5f5886..b20c9768d9f3f 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -410,7 +410,7 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
*/
__skb_queue_purge(&n->arp_queue);
n->arp_queue_len_bytes = 0;
- n->output = neigh_blackhole;
+ WRITE_ONCE(n->output, neigh_blackhole);
if (n->nud_state & NUD_VALID)
n->nud_state = NUD_NOARP;
else
@@ -920,7 +920,7 @@ static void neigh_suspect(struct neighbour *neigh)
{
neigh_dbg(2, "neigh %p is suspected\n", neigh);
- neigh->output = neigh->ops->output;
+ WRITE_ONCE(neigh->output, neigh->ops->output);
}
/* Neighbour state is OK;
@@ -932,7 +932,7 @@ static void neigh_connect(struct neighbour *neigh)
{
neigh_dbg(2, "neigh %p is connected\n", neigh);
- neigh->output = neigh->ops->connected_output;
+ WRITE_ONCE(neigh->output, neigh->ops->connected_output);
}
static void neigh_periodic_work(struct work_struct *work)
@@ -1449,7 +1449,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
if (n2)
n1 = n2;
}
- n1->output(n1, skb);
+ READ_ONCE(n1->output)(n1, skb);
if (n2)
neigh_release(n2);
rcu_read_unlock();
@@ -3145,7 +3145,7 @@ int neigh_xmit(int index, struct net_device *dev,
rcu_read_unlock();
goto out_kfree_skb;
}
- err = neigh->output(neigh, skb);
+ err = READ_ONCE(neigh->output)(neigh, skb);
rcu_read_unlock();
}
else if (index == NEIGH_LINK_TABLE) {
