From 03be42ab847f04a89d207d98fdb28048cfedf72d Mon Sep 17 00:00:00 2001
From: Scott Shawcroft <scott@tannewt.org>
Date: Fri, 8 Mar 2019 15:29:14 -0800
Subject: Enter safe mode when an allocation is attempted on an uninitialized
 heap.

---
 py/gc.c | 13 +++++++++++++
 py/gc.h |  1 +
 2 files changed, 14 insertions(+)

(limited to 'py')

diff --git a/py/gc.c b/py/gc.c
index 1f5cd8d01..e0b77c4cf 100755
--- a/py/gc.c
+++ b/py/gc.c
@@ -31,6 +31,8 @@
 #include "py/gc.h"
 #include "py/runtime.h"
 
+#include "supervisor/shared/safe_mode.h"
+
 #if MICROPY_ENABLE_GC
 
 #if MICROPY_DEBUG_VERBOSE // print debugging info
@@ -182,6 +184,13 @@ void gc_init(void *start, void *end) {
     DEBUG_printf("  pool at %p, length " UINT_FMT " bytes, " UINT_FMT " blocks\n", MP_STATE_MEM(gc_pool_start), gc_pool_block_len * BYTES_PER_BLOCK, gc_pool_block_len);
 }
 
+void gc_deinit() {
+    // Run any finalizers before we stop using the heap.
+    gc_sweep_all();
+
+    MP_STATE_MEM(gc_pool_start) = 0;
+}
+
 void gc_lock(void) {
     GC_ENTER();
     MP_STATE_MEM(gc_lock_depth)++;
@@ -463,6 +472,10 @@ void *gc_alloc(size_t n_bytes, bool has_finaliser, bool long_lived) {
         return NULL;
     }
 
+    if (MP_STATE_MEM(gc_pool_start) == 0) {
+        reset_into_safe_mode(GC_ALLOC_OUTSIDE_VM);
+    }
+
     GC_ENTER();
 
     // check if GC is locked
diff --git a/py/gc.h b/py/gc.h
index 64f4b0d17..c05e006b4 100644
--- a/py/gc.h
+++ b/py/gc.h
@@ -32,6 +32,7 @@
 #include "py/misc.h"
 
 void gc_init(void *start, void *end);
+void gc_deinit(void);
 
 // These lock/unlock functions can be nested.
 // They can be used to prevent the GC from allocating/freeing.
-- 
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