From 0915689c6bc2ec94164340f3924adc4afbbb7051 Mon Sep 17 00:00:00 2001
From: Vadim Skipin <vadim.skipin@clickhouse.com>
Date: Wed, 6 May 2026 20:28:56 +0000
Subject: [PATCH] Assert on queue layout

---
 include/silk/util/bounded-queue.h | 8 ++++++++
 include/silk/util/queue.h         | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/include/silk/util/bounded-queue.h b/include/silk/util/bounded-queue.h
index 1732e03..bc67da2 100644
--- a/include/silk/util/bounded-queue.h
+++ b/include/silk/util/bounded-queue.h
@@ -116,12 +116,20 @@ class BoundedQueue
 
     static_assert(sizeof(Slot) == CACHELINE_SIZE);
 
+    // Match offsets and stride used by src/gdb/fiber.py::_walk_bounded_queue
+    static_assert(offsetof(Slot, sequence) == 0);
+    static_assert(offsetof(Slot, value) == 8);
+
     //
     // State.
     //
 
     uint64_t mask;
     std::unique_ptr<Slot[]> slots;
+
+    // src/gdb/fiber.py::_walk_bounded_queue reads enqueuePos at offset 64 and
+    // dequeuePos at offset 128 (mask=8 bytes, slots=8 bytes, then 2 x cacheline).
+    // Reordering or inserting fields here requires updating that script.
     alignas(CACHELINE_SIZE) std::atomic<uint64_t> enqueuePos{};
     alignas(CACHELINE_SIZE) std::atomic<uint64_t> dequeuePos{};
 };
diff --git a/include/silk/util/queue.h b/include/silk/util/queue.h
index ec1b5fb..6d6cfc1 100644
--- a/include/silk/util/queue.h
+++ b/include/silk/util/queue.h
@@ -30,6 +30,10 @@ class QueueBase
 
     static_assert(sizeof(QueueNode) == CACHELINE_SIZE);
 
+    // Match offsets used by src/gdb/fiber.py::_walk_queue
+    static_assert(offsetof(QueueNode, next) == 8);
+    static_assert(offsetof(QueueNode, value) == 16);
+
     static void initialize() noexcept;
     static void destroy() noexcept;