From: Thierry FOURNIER <thierry.fournier@ozon.io>
Date: Fri, 25 May 2018 13:03:50 +0000 (+0200)
Subject: BUG/MAJOR: lua: Dead lock with sockets
X-Git-Tag: v1.9-dev1~228
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7e4ee47accdb93925ddfc18cf6f181ff334abcdc;p=thirdparty%2Fhaproxy.git

BUG/MAJOR: lua: Dead lock with sockets

In some cases, when we are waiting for data and the socket
timeout expires, we have a dead lock. The Lua socket locks
the applet socket, and call for a notify. The notify
immediately executes code and try to acquire the same lock,
so ... dead lock.

stream_int_notify() cant be used because it wakeup the applet
task only if the stream have changes. The changes are forces
by Lua, but not repported on the stream.

stream_int_update_applet() cant be used because the deadlock.

So, I inconditionnaly wakeup the applet. This wake is performed
asynchronously, and will call a stream_int_notify().

This patch must be backported in 1.6, 1.7 and 1.8
---

diff --git a/src/hlua.c b/src/hlua.c
index 03e961c378..48de5cba55 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -1766,8 +1766,7 @@ __LJMP static int hlua_socket_receive_yield(struct lua_State *L, int status, lua
 	co_skip(oc, len + skip_at_end);
 
 	/* Don't wait anything. */
-	stream_int_notify(&s->si[0]);
-	stream_int_update_applet(&s->si[0]);
+	appctx_wakeup(appctx);
 
 	/* If the pattern reclaim to read all the data
 	 * in the connection, got out.