BUG/MEDIUM: conn-stream: Set back CS to RDY state when the appctx is created
When an appctx is created on the server side, we now set the corresponding
conn-stream to ready state (CS_ST_RDY). When it happens, the backend
conn-stream is in CS_ST_INI state. It is not consistant to let the
conn-stream in this state because it means it is possible to have a target
installed in CS_ST_INI state, while with a connection, the conn-stream is
switch to CS_ST_RDY or CS_ST_EST state.
It is especially anbiguous because we may be tempted to think there is no
endpoint attached to the conn-stream before the CS_ST_CON state. And it is
indeed the reason for a bug leading to a crash because a cs_detach_endp() is
performed if an abort is detected on the backend conn-stream in CS_ST_INI
state. With a mux or a appctx attached to the conn-stream, "->endp" field is
set to NULL. It is unexpected. The API will be changed to be sure it is not
possible. But it exposes a consistency issue with applets.
So, the conn-stream must not stay in CS_ST_INI state when an appctx is
attached. But there is no reason to set it in CS_ST_REQ. The conn-stream
must be set to CS_ST_RDY to handle applets and connections in the same
way. Note that if only the target is set but no appctx is created, the
backend conn-stream is switched from CS_ST_INI to CS_ST_REQ state to be able
to create the corresponding appctx. This part is unchanged.
This patch depends on the commit "MINOR: backend: Don't allow to change
backend applet".
The ambiguity exists on previous versions. But the issue is
2.6-specific. Thus, no backport is needed.
diff --git a/src/backend.c b/src/backend.c
index 12f9a65..6bff6ff 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -2113,7 +2113,7 @@
/* This function initiates a server connection request on a conn-stream
* already in CS_ST_REQ state. Upon success, the state goes to CS_ST_ASS for
* a real connection to a server, indicating that a server has been assigned,
- * or CS_ST_EST for a successful connection to an applet. It may also return
+ * or CS_ST_RDY for a successful connection to an applet. It may also return
* CS_ST_QUE, or CS_ST_CLO upon error.
*/
void back_handle_st_req(struct stream *s)
@@ -2126,12 +2126,14 @@
DBG_TRACE_ENTER(STRM_EV_STRM_PROC|STRM_EV_CS_ST, s);
if (unlikely(obj_type(s->target) == OBJ_TYPE_APPLET)) {
- /* the applet directly goes to the EST state */
- struct appctx *appctx = cs_appctx(s->csb);
+ struct appctx *appctx;
- if (!appctx)
- appctx = cs_applet_create(cs, objt_applet(s->target));
-
+ /* The target is an applet but the CS is in CS_ST_REQ. Thus it
+ * means no appctx are attached to the CS. Otherwise, it will be
+ * in CS_ST_RDY state. So, try to create the appctx now.
+ */
+ BUG_ON(cs_appctx(cs));
+ appctx = cs_applet_create(cs, objt_applet(s->target));
if (!appctx) {
/* No more memory, let's immediately abort. Force the
* error code to ignore the ERR_LOCAL which is not a
@@ -2150,15 +2152,7 @@
goto end;
}
- if (tv_iszero(&s->logs.tv_request))
- s->logs.tv_request = now;
- s->logs.t_queue = tv_ms_elapsed(&s->logs.tv_accept, &now);
- cs->state = CS_ST_EST;
- s->conn_err_type = STRM_ET_NONE;
- be_set_sess_last(s->be);
-
DBG_TRACE_STATE("applet registered", STRM_EV_STRM_PROC|STRM_EV_CS_ST, s);
- /* let back_establish() finish the job */
goto end;
}
@@ -2406,6 +2400,19 @@
struct channel *rep = &s->res;
DBG_TRACE_ENTER(STRM_EV_STRM_PROC|STRM_EV_CS_ST, s);
+
+ if (unlikely(obj_type(s->target) == OBJ_TYPE_APPLET)) {
+ /* Here the appctx must exists because the CS was set to
+ * CS_ST_RDY state when the appctx was created.
+ */
+ BUG_ON(!cs_appctx(s->csb));
+
+ if (tv_iszero(&s->logs.tv_request))
+ s->logs.tv_request = now;
+ s->logs.t_queue = tv_ms_elapsed(&s->logs.tv_accept, &now);
+ be_set_sess_last(s->be);
+ }
+
/* We know the connection at least succeeded, though it could have
* since met an error for any other reason. At least it didn't time out
* even though the timeout might have been reported right after success.
diff --git a/src/conn_stream.c b/src/conn_stream.c
index 29bf49b..e753749 100644
--- a/src/conn_stream.c
+++ b/src/conn_stream.c
@@ -468,6 +468,8 @@
appctx->t->nice = __cs_strm(cs)->task->nice;
cs_cant_get(cs);
appctx_wakeup(appctx);
+
+ cs->state = CS_ST_RDY;
return appctx;
}