From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Fri, 9 Oct 2026 07:28:26 +0000 (+0200)
Subject: BUG/MINOR: check: do not inspect errno if conn FDLESS
X-Git-Tag: v3.5-dev10~174
X-Git-Url: https://git.kaiwu.me/$%7BISSUES%7D/static/gitweb.js?a=commitdiff_plain;h=ed2bea8c74b3d9575d02e45ec875d29be58ed6ab;p=haproxy.git

BUG/MINOR: check: do not inspect errno if conn FDLESS

On check failure, conn errno is inspected via
retrieve_errno_from_socket(), which relies on the connection FD. When
using a CO_FL_FDLESS connection, this triggers a BUG_ON().

This causes crashes for QUIC backend checks, available since 3.3. To fix
this, simply skip call to retrieve_errno_from_socket() when CO_FL_FDLESS
is set.

This must be backported up to 3.3.
---

diff --git a/src/check.c b/src/check.c
index 78bde2e89..2f9fec36a 100644
--- a/src/check.c
+++ b/src/check.c
@@ -816,7 +816,7 @@ void chk_report_conn_err(struct check *check, int errno_bck, int expired)
 	}
 
 	errno = unclean_errno(errno_bck);
-	if (conn && !errno)
+	if (conn && !errno && !(conn->flags & CO_FL_FDLESS))
 		retrieve_errno_from_socket(conn);
 
 	TRACE_ENTER(CHK_EV_HCHK_END|CHK_EV_HCHK_ERR, check, 0, 0, (size_t[]){expired});