From d4b96af062397e9de88fa2580da52049aa82f0bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Tue, 10 Mar 2026 18:25:37 +0100
Subject: [PATCH] Enforce isc_work enqueue loop affinity

Add a REQUIRE(isc_loop() == loop) assertion to isc_work_enqueue()
to strictly enforce that work is enqueued from the loop it is
assigned to. This loudly prohibits cross-thread queue manipulation
before it inevitably turns into a concurrency debugging nightmare.

(cherry picked from commit f1311d2d196d381b2170c4b3d54262874a5d424e)
---
 lib/isc/work.c        | 1 +
 tests/isc/work_test.c | 9 ++-------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/lib/isc/work.c b/lib/isc/work.c
index 4391b2d2fa..0b7cdf5743 100644
--- a/lib/isc/work.c
+++ b/lib/isc/work.c
@@ -58,6 +58,7 @@ isc_work_enqueue(isc_loop_t *loop, isc_work_cb work_cb,
 	int r;
 
 	REQUIRE(VALID_LOOP(loop));
+	REQUIRE(isc_loop() == loop);
 	REQUIRE(work_cb != NULL);
 	REQUIRE(after_work_cb != NULL);
 
diff --git a/tests/isc/work_test.c b/tests/isc/work_test.c
index 3c126ee613..5e0184cd52 100644
--- a/tests/isc/work_test.c
+++ b/tests/isc/work_test.c
@@ -56,13 +56,8 @@ after_work_cb(void *arg) {
 }
 
 static void
-work_enqueue_cb(void *arg) {
-	UNUSED(arg);
-	uint32_t tid = isc_loopmgr_nloops(loopmgr) - 1;
-
-	isc_loop_t *loop = isc_loop_get(loopmgr, tid);
-
-	isc_work_enqueue(loop, work_cb, after_work_cb, loopmgr);
+work_enqueue_cb(void *arg ISC_ATTR_UNUSED) {
+	isc_work_enqueue(isc_loop(), work_cb, after_work_cb, NULL);
 }
 
 ISC_RUN_TEST_IMPL(isc_work_enqueue) {