From ccd44b69e5774ca7158c7445fa8c619a91840b32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Witold=20Kr=C4=99cicki?= <wpk@isc.org>
Date: Tue, 10 Dec 2019 10:05:15 +0100
Subject: [PATCH] Fix a potential lock-order-inversion in tcp listening code

---
 lib/isc/netmgr/tcp.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index a996acfb01..e1bbeab48e 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -186,10 +186,13 @@ isc_nm_listentcp(isc_nm_t *mgr, isc_nmiface_t *iface,
 		isc__nm_put_ievent(mgr, ievent);
 	} else {
 		nsock->tid = isc_random_uniform(mgr->nworkers);
-		LOCK(&nsock->lock);
 		isc__nm_enqueue_ievent(&mgr->workers[nsock->tid],
 				       (isc__netievent_t *) ievent);
-		WAIT(&nsock->cond, &nsock->lock);
+
+		LOCK(&nsock->lock);
+		while (!atomic_load(&nsock->listening)) {
+			WAIT(&nsock->cond, &nsock->lock);
+		}
 		UNLOCK(&nsock->lock);
 	}