| From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
| From: "Jason A. Donenfeld" <Jason@zx2c4.com> |
| Date: Wed, 6 May 2020 15:33:04 -0600 |
| Subject: [PATCH] wireguard: send/receive: cond_resched() when processing |
| worker ringbuffers |
| |
| commit 4005f5c3c9d006157ba716594e0d70c88a235c5e upstream. |
| |
| Users with pathological hardware reported CPU stalls on CONFIG_ |
| PREEMPT_VOLUNTARY=y, because the ringbuffers would stay full, meaning |
| these workers would never terminate. That turned out not to be okay on |
| systems without forced preemption, which Sultan observed. This commit |
| adds a cond_resched() to the bottom of each loop iteration, so that |
| these workers don't hog the core. Note that we don't need this on the |
| napi poll worker, since that terminates after its budget is expended. |
| |
| Suggested-by: Sultan Alsawaf <sultan@kerneltoast.com> |
| Reported-by: Wang Jian <larkwang@gmail.com> |
| Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") |
| Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> |
| --- |
| drivers/net/wireguard/receive.c | 2 ++ |
| drivers/net/wireguard/send.c | 4 ++++ |
| 2 files changed, 6 insertions(+) |
| |
| --- a/drivers/net/wireguard/receive.c |
| +++ b/drivers/net/wireguard/receive.c |
| @@ -516,6 +516,8 @@ void wg_packet_decrypt_worker(struct wor |
| &PACKET_CB(skb)->keypair->receiving)) ? |
| PACKET_STATE_CRYPTED : PACKET_STATE_DEAD; |
| wg_queue_enqueue_per_peer_napi(skb, state); |
| + if (need_resched()) |
| + cond_resched(); |
| } |
| } |
| |
| --- a/drivers/net/wireguard/send.c |
| +++ b/drivers/net/wireguard/send.c |
| @@ -281,6 +281,8 @@ void wg_packet_tx_worker(struct work_str |
| |
| wg_noise_keypair_put(keypair, false); |
| wg_peer_put(peer); |
| + if (need_resched()) |
| + cond_resched(); |
| } |
| } |
| |
| @@ -304,6 +306,8 @@ void wg_packet_encrypt_worker(struct wor |
| } |
| wg_queue_enqueue_per_peer(&PACKET_PEER(first)->tx_queue, first, |
| state); |
| + if (need_resched()) |
| + cond_resched(); |
| } |
| } |
| |