From f2e62de7d99ae4061e72e313d3aa9779a15839a9 Mon Sep 17 00:00:00 2001
From: Alexander Motin <mav@FreeBSD.org>
Date: Sun, 15 Mar 2015 16:18:03 +0000
Subject: [PATCH] Close potential race on blockif_close().

Reported by:	vangyzen
MFC after:	2 weeks
---
 usr.sbin/bhyve/block_if.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/usr.sbin/bhyve/block_if.c b/usr.sbin/bhyve/block_if.c
index 68a9bae9c901..58960ca0c757 100644
--- a/usr.sbin/bhyve/block_if.c
+++ b/usr.sbin/bhyve/block_if.c
@@ -579,7 +579,9 @@ blockif_close(struct blockif_ctxt *bc)
 	/*
 	 * Stop the block i/o thread
 	 */
+	pthread_mutex_lock(&bc->bc_mtx);
 	bc->bc_closing = 1;
+	pthread_mutex_unlock(&bc->bc_mtx);
 	pthread_cond_broadcast(&bc->bc_cond);
 	for (i = 0; i < BLOCKIF_NUMTHR; i++)
 		pthread_join(bc->bc_btid[i], &jval);