BUG/MAJOR: lua: properly dequeue hlua_applet_wakeup() for new scheduler
The recent scheduler change broke the Lua co-sockets due to
hlua_applet_wakeup() returning NULL after waking the applet up. With the
previous scheduler, returning NULL was a way to do nothing on return.
With the new one it keeps TASK_RUNNING set, causing all new notifications
to end up into t->pending_state instead of t->state, and prevents the
task from being added into the run queue again, so and it's never woken
up anymore.
The applet keeps waking up, causing hlua_socket_handler() to do nothing
new, then si_applet_wake_cb() calling stream_int_notify() to try to wake
the task up, which it can't do due to the TASK_RUNNING flag, then decide
that since the associated task is not in the run queue, it needs to call
stream_int_update_applet() to propagate the update. This last one finds
that the applet needs to be woken up to deal with the last reported events
and calling appctx_wakeup() again. Previously, this situation didn't exist
because the task was always added in the run queue despite the TASK_RUNNING
flag.
By returning the task instead in hlua_applet_wakeup(), we can ensure its
flag is properly cleared and the task is requeued if needed or just sits
waiting for new events to happen.
This fix requires the previous ones ("BUG/MINOR: lua: always detach the
tcp/http tasks before freeing them") and MINOR: task: always preinitialize
the task's timeout in task_init().
Thanks to Thierry, Christopher and Emeric for the long head-scratching
session!
No backport is needed as the bug doesn't appear in older versions and
it's unsure whether we'll not break something by backporting it.
diff --git a/src/hlua.c b/src/hlua.c
index 437f427..0045a1c 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -5971,7 +5971,7 @@
*/
si_applet_cant_put(si);
appctx_wakeup(ctx);
- return NULL;
+ return t;
}
static int hlua_applet_tcp_init(struct appctx *ctx, struct proxy *px, struct stream *strm)