From e21300c15cd8365017be856f944efa4db7b1cb95 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Mon, 4 May 2020 17:53:42 -0600 Subject: wireguard: send/receive: cond_resched() when processing worker ringbuffers 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 Reported-by: Wang Jian Signed-off-by: Jason A. Donenfeld --- drivers/net/wireguard/receive.c | 1 + drivers/net/wireguard/send.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c index 267f202f1931..35831fed03c2 100644 --- a/drivers/net/wireguard/receive.c +++ b/drivers/net/wireguard/receive.c @@ -516,6 +516,7 @@ void wg_packet_decrypt_worker(struct work_struct *work) &PACKET_CB(skb)->keypair->receiving)) ? PACKET_STATE_CRYPTED : PACKET_STATE_DEAD; wg_queue_enqueue_per_peer_napi(skb, state); + cond_resched(); } } diff --git a/drivers/net/wireguard/send.c b/drivers/net/wireguard/send.c index 3e030d614df5..fbfc1ddd4e26 100644 --- a/drivers/net/wireguard/send.c +++ b/drivers/net/wireguard/send.c @@ -281,6 +281,7 @@ void wg_packet_tx_worker(struct work_struct *work) wg_noise_keypair_put(keypair, false); wg_peer_put(peer); + cond_resched(); } } @@ -304,6 +305,7 @@ void wg_packet_encrypt_worker(struct work_struct *work) } wg_queue_enqueue_per_peer(&PACKET_PEER(first)->tx_queue, first, state); + cond_resched(); } } -- cgit v1.2.3-59-g8ed1b