[lxc-devel] [lxd/master] task/group: Moves wait group Done() after g.running update

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From ef74ab3e6ea9a635074d687d31cbdf29bc9a7c63 Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Tue, 16 Jul 2019 13:35:04 +0100
Subject: [PATCH] task/group: Moves wait group Done() after g.running update to
 avoid race on task end

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 lxd/task/group.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lxd/task/group.go b/lxd/task/group.go
index ac086bb28d..d40c257225 100644
--- a/lxd/task/group.go
+++ b/lxd/task/group.go
@@ -59,11 +59,13 @@ func (g *Group) Start() {
 
 		go func(i int) {
 			task.loop(ctx)
-			g.wg.Done()
 
+			// Ensure running map is updated before wait group Done() is called.
 			g.mu.Lock()
 			g.running[i] = false
 			g.mu.Unlock()
+
+			g.wg.Done()
 		}(i)
 	}
 }