feat: add lab-rv32i-freertos-static-task card

2026-07-21 19:14:20 +02:00
commit 62efc0c91f
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+# K08 — dynamic/static task storage, deletion and lifetime
+
+K08 gives identical worker behavior two storage policies:
+
+- `DynamicTask` calls `xTaskCreate`; FreeRTOS allocates TCB and stack from
+  `heap_4` and the idle task later reclaims them after self-deletion;
+- `StaticTask` calls `xTaskCreateStatic` with caller-owned `StaticTask_t` and
+  `StackType_t[]` located in `.bss`; task deletion never transfers ownership of
+  those buffers to the kernel.
+
+Both wrappers remain non-copyable, non-movable and non-virtual. The static
+storage is a separate `StaticTaskStorage<N>` object so its TCB/stack are visibly
+caller supplied and their lifetime is independent from the wrapper's handle.
+
+## Measured Hazard3 result
+
+```text
+dynamic heap cost          = 0x470 = 1136 bytes
+free before idle cleanup   = 0x3b80
+free after idle cleanup    = 0x3ff0 (baseline)
+static stack words         = 0x100 = 256
+static stack bytes         = 0x400 = 1024
+```
+
+The dynamic worker sets `completed` and clears its wrapper handle before
+`vTaskDelete(nullptr)`, but its kernel storage is only placed on the termination
+list at that point. A static verifier first captures the reduced heap, blocks
+for two ticks to let idle run, then observes full recovery.
+
+## Evidence
+
+| Stage | Heap relation |
+| --- | --- |
+| baseline | initialized `heap_4`, no worker kernel object |
+| dynamic start | free decreases by 1136 B |
+| static start | free unchanged from dynamic-start value |
+| static verifier create | free unchanged again |
+| workers completed/self-deleted | dynamic 1136 B still not reclaimed |
+| verifier blocks, idle cleans | free increases by 1136 B to baseline |
+
+Addresses prove dynamic TCB/stack lie in `ucHeap`, while the static TCB and
+stack equal the caller storage addresses in `.bss`. Both workers compute
+500500.
+
+## Build
+
+```sh
+make check
+```
+
+Expected:
+
+```text
+PASS host: dynamic/static policies, stable caller storage and units
+PASS ABI: dynamic/static trampolines; caller storage in .bss; no vtable
+PASS task01: dynamic/static task storage + idle cleanup
+```
+
+## Debug
+
+```gdb
+b task_storage_debug_checkpoint
+p g_heap_baseline
+p g_heap_after_dynamic_start
+p g_heap_after_static_start
+p g_heap_before_idle_cleanup
+p g_heap_after_idle_cleanup
+p/x g_dynamic_tcb
+p/x g_dynamic_stack_low
+p/x g_static_tcb
+p/x g_static_tcb_storage
+p/x g_static_stack_low
+p/x g_static_stack_storage
+p g_static_stack_words
+p g_static_stack_bytes
+p g_task_storage_pass
+```
+
+## Scope boundary
+
+Task deletion does not safely unwind arbitrary application resources on its
+stack. The workers arrange normal member completion before self-deletion. Static
+storage must outlive the task and must not be reused merely because a stop was
+requested; completion/deletion must be established first.
+