From 86e3f78c8d324b410fbe79dcdc702a366e5c5341 Mon Sep 17 00:00:00 2001 From: Maciej Fijalkowski Date: Tue, 25 Jan 2022 17:04:44 +0100 Subject: [PATCH] ice: xsk: Avoid potential dead AF_XDP Tx processing Commit 9610bd988df9 ("ice: optimize XDP_TX workloads") introduced @next_dd and @next_rs to ice_tx_ring struct. Currently, their state is not restored in ice_clean_tx_ring(), which was not causing any troubles as the XDP rings are gone after we're done with XDP prog on interface. For upcoming usage of mentioned fields in AF_XDP, this might expose us to a potential dead Tx side. Scenario would look like following (based on xdpsock): - two xdpsock instances are spawned in Tx mode - one of them is killed - XDP prog is kept on interface due to the other xdpsock still running * this means that XDP rings stayed in place - xdpsock is launched again on same queue id that was terminated on - @next_dd and @next_rs setting is bogus, therefore transmit side is broken To protect us from the above, restore the initial @next_rs and @next_dd values when cleaning the Tx ring. Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Reviewed-by: Alexander Lobakin Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20220125160446.78976-7-maciej.fijalkowski@intel.com --- drivers/net/ethernet/intel/ice/ice_txrx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c index e661d0e45b9b7..73f60493209d8 100644 --- a/drivers/net/ethernet/intel/ice/ice_txrx.c +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c @@ -173,6 +173,8 @@ void ice_clean_tx_ring(struct ice_tx_ring *tx_ring) tx_ring->next_to_use = 0; tx_ring->next_to_clean = 0; + tx_ring->next_dd = ICE_RING_QUARTER(tx_ring) - 1; + tx_ring->next_rs = ICE_RING_QUARTER(tx_ring) - 1; if (!tx_ring->netdev) return;