From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Thu, 23 Apr 2026 12:23:01 +0000 (+0200)
Subject: BUG/MINOR: mux_quic: open an idle QCS on reset on BE side
X-Git-Tag: v3.4.0~68
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=802a3b72884b619694c57c51d5f9795b2934dff4;p=thirdparty%2Fhaproxy.git

BUG/MINOR: mux_quic: open an idle QCS on reset on BE side

On the backend side, a QCS may be opened but resetted immediately. No
STREAM frame will be emitted prior to the RESET_STREAM. When the latter
is sent, qcs_close_local() will mark the QCS Tx channel as closed.

In this case, a BUG_ON() would be triggered as there is QCS Tx channel
is not yet marked as opened. To prevent this, add a qcs_idle_open() call
when the stream is resetted, but only for the backend side.

This should be backported up to 3.3.
---

diff --git a/src/mux_quic.c b/src/mux_quic.c
index b36799a6b..2edc88b78 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -1737,6 +1737,10 @@ void qcc_reset_stream(struct qcs *qcs, int err, int tevt)
 	qcs->flags |= QC_SF_TO_RESET;
 	qcs->err = err;
 
+	/* On BE side, a QCS may be resetted before any data emission. */
+	if (conn_is_back(qcs->qcc->conn))
+		qcs_idle_open(qcs);
+
 	if (diff) {
 		const int soft_blocked = qfctl_sblocked(&qcc->tx.fc);