v3-0002-Assert-that-spinlocks-are-not-double-released.patch

From 3354ee5fd668b00b47920faffe454542a365932f Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Thu, 1 Aug 2024 11:00:20 +1200
Subject: [PATCH v3 2/3] Assert that spinlocks are not double-released.

---
 src/include/storage/spin.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/include/storage/spin.h b/src/include/storage/spin.h
index 326a2711f23..9414c111db8 100644
--- a/src/include/storage/spin.h
+++ b/src/include/storage/spin.h
@@ -109,6 +109,12 @@ SpinLockInit(volatile slock_t *lock)
 static inline void
 SpinLockRelease(volatile slock_t *lock)
 {
+	/*
+	 * Use a relaxed load to see that it's currently held.  That's OK because
+	 * we expect the calling thread to be the one that set it.
+	 */
+	Assert(!pg_atomic_unlocked_test_flag(lock));
+
 	pg_atomic_clear_flag(lock);
 }
 
-- 
2.45.2