commit 8b8d55be7e94ee3d758d41a21fa86a036e91a264
Author: Christopher Faulet <cfaulet@haproxy.com>
Date:   Wed Apr 25 10:34:45 2018 +0200

    BUG/MINOR: lua/threads: Make lua's tasks sticky to the current thread
    
    PiBa-NL reported a bug with tasks registered in lua when HAProxy is started with
    serveral threads. These tasks have not specific affinity with threads so they
    can be woken up on any threads. So, it is impossbile for these tasks to handled
    cosockets or applets, because cosockets and applets are sticky on the thread
    which created them. It is forbbiden to manipulate a cosocket from another
    thread.
    
    So to fix the bug, tasks registered in lua are now sticky to the current
    thread. Because these tasks can be registered before threads creation, the
    affinity is set the first time a lua's task is processed.
    
    This patch must be backported in HAProxy 1.8.
    
    (cherry picked from commit 5bc9972ed836517924eea91954d255d317a53418)
    Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/src/hlua.c b/src/hlua.c
index d4b7ce91..bd0b87e3 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -5513,6 +5513,9 @@ static struct task *hlua_process_task(struct task *task)
 	struct hlua *hlua = task->context;
 	enum hlua_exec status;
 
+	if (task->thread_mask == MAX_THREADS_MASK)
+		task_set_affinity(task, tid_bit);
+
 	/* If it is the first call to the task, we must initialize the
 	 * execution timeouts.
 	 */