Commit b9c89fa1 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

neighbour: Use rcu_dereference() in pneigh_get_{first,next}(). 



Now pneigh_entry is guaranteed to be alive during the
RCU critical section even without holding tbl->lock.

Let's use rcu_dereference() in pneigh_get_{first,next}().

Note that neigh_seq_start() still holds tbl->lock for the
normal neighbour entry.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250716221221.442239-12-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 32d5eaab

net/core/neighbour.c

+5 −5
Original line number Diff line number Diff line
@@ -3309,10 +3309,10 @@ static struct pneigh_entry *pneigh_get_first(struct seq_file *seq) 


	state->flags |= NEIGH_SEQ_IS_PNEIGH;

	for (bucket = 0; bucket <= PNEIGH_HASHMASK; bucket++) {

		pn = rcu_dereference_protected(tbl->phash_buckets[bucket], 1);

		pn = rcu_dereference(tbl->phash_buckets[bucket]);



		while (pn && !net_eq(pneigh_net(pn), net))

			pn = rcu_dereference_protected(pn->next, 1);

			pn = rcu_dereference(pn->next);

		if (pn)

			break;

	}
@@ -3330,17 +3330,17 @@ static struct pneigh_entry *pneigh_get_next(struct seq_file *seq, 
	struct neigh_table *tbl = state->tbl;



	do {

		pn = rcu_dereference_protected(pn->next, 1);

		pn = rcu_dereference(pn->next);

	} while (pn && !net_eq(pneigh_net(pn), net));



	while (!pn) {

		if (++state->bucket > PNEIGH_HASHMASK)

			break;



		pn = rcu_dereference_protected(tbl->phash_buckets[state->bucket], 1);

		pn = rcu_dereference(tbl->phash_buckets[state->bucket]);



		while (pn && !net_eq(pneigh_net(pn), net))

			pn = rcu_dereference_protected(pn->next, 1);

			pn = rcu_dereference(pn->next);

		if (pn)

			break;

	}