Commit ed6cd6a1 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Jakub Kicinski
Browse files

net, neigh: Set lower cap for neigh_managed_work rearming 



Yuwei reported that plain reuse of DELAY_PROBE_TIME to rearm work queue
in neigh_managed_work is problematic if user explicitly configures the
DELAY_PROBE_TIME to 0 for a neighbor table. Such misconfig can then hog
CPU to 100% processing the system work queue. Instead, set lower interval
bound to HZ which is totally sufficient. Yuwei is additionally looking
into making the interval separately configurable from DELAY_PROBE_TIME.

Reported-by: default avatarYuwei Wang <wangyuweihx@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/netdev/797c3c53-ce1b-9f60-e253-cda615788f4a@iogearbox.net


Reviewed-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/3b8c5aa906c52c3a8c995d1b2e8ccf650ea7c716.1653432794.git.daniel@iogearbox.net


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b3b1a175

net/core/neighbour.c

+1 −1
Original line number Diff line number Diff line
@@ -1579,7 +1579,7 @@ static void neigh_managed_work(struct work_struct *work) 
	list_for_each_entry(neigh, &tbl->managed_list, managed_list)

		neigh_event_send_probe(neigh, NULL, false);

	queue_delayed_work(system_power_efficient_wq, &tbl->managed_work,

			   NEIGH_VAR(&tbl->parms, DELAY_PROBE_TIME));

			   max(NEIGH_VAR(&tbl->parms, DELAY_PROBE_TIME), HZ));

	write_unlock_bh(&tbl->lock);

}