From 030ed4b73873e1d93d887d679e65b9e851ec3b1e Mon Sep 17 00:00:00 2001 From: Christopher Faulet Date: Thu, 28 May 2020 13:58:34 +0200 Subject: [PATCH] BUG/MEDIUM: checks: Don't blindly subscribe for receive if waiting for connect When an health check is waiting for a connection establishment, it subscribe for receive or send events, depending on the next rule to be evaluated. For subscription for send events, there is no problem. It works as expected. For subscription for receive events, It only works for HTTP checks because the underlying multiplexer takes care to do a receive before subscribing again, updating the fd state. For TCP checks, the PT multiplexer only forwards subscriptions at the transport layer. So the check itself is woken up. This leads to a subscribe/notify loop waiting the connection establishment or a timeout, uselessly eating CPU. Thus, when a check is waiting for a connect, instead of blindly resubscribe for receive events when it is woken up, we now try to receive data. This patch should fix the issue #635. No backport needed. --- src/checks.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/src/checks.c b/src/checks.c index 8b852867f..9b4e41c35 100644 --- a/src/checks.c +++ b/src/checks.c @@ -2623,6 +2623,7 @@ static int tcpcheck_main(struct check *check) struct connection *conn = cs_conn(cs); int must_read = 1, last_read = 0; int ret, retcode = 0; + enum tcpcheck_eval_ret eval_ret; /* here, we know that the check is complete or that it failed */ if (check->result != CHK_RES_UNKNOWN) @@ -2647,12 +2648,17 @@ static int tcpcheck_main(struct check *check) if (next && next->action == TCPCHK_ACT_SEND) { if (!(check->wait_list.events & SUB_RETRY_SEND)) conn->mux->subscribe(cs, SUB_RETRY_SEND, &check->wait_list); + goto out; } else { - if (!(check->wait_list.events & SUB_RETRY_RECV)) - conn->mux->subscribe(cs, SUB_RETRY_RECV, &check->wait_list); + eval_ret = tcpcheck_eval_recv(check, check->current_step); + if (eval_ret == TCPCHK_EVAL_STOP) + goto out_end_tcpcheck; + else if (eval_ret == TCPCHK_EVAL_WAIT) + goto out; + last_read = ((conn->flags & CO_FL_ERROR) || (cs->flags & (CS_FL_ERROR|CS_FL_EOS))); + must_read = 0; } - goto out; } rule = LIST_NEXT(&check->current_step->list, typeof(rule), list); } @@ -2713,8 +2719,6 @@ static int tcpcheck_main(struct check *check) /* Now evaluate the tcp-check rules */ list_for_each_entry_from(rule, check->tcpcheck_rules->list, list) { - enum tcpcheck_eval_ret eval_ret; - check->code = 0; switch (rule->action) { case TCPCHK_ACT_CONNECT: