crypto: fix lockup when stack is shutdown while waiting for result of HCI Command, e.g. LE Read Local P256 Public Key

CHANGELOG.md

@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Fixed
+- Crypto: fix lockup when stack is shutdown while waiting for result of HCI Command, e.g. LE Read Local P256 Public Key
+
+## Changes December 2018
+
 ### Changed
 - L2CAP: provide channel mode (basic/ertm) and fcs option in L2CAP_EVENT_CHANNEL_OPENED 
 - RFCOMM: support L2CAP ERTM. Callbacks passed to rfcomm_enable_l2cap_ertm() are used to manage ERTM buffers

src/btstack_crypto.c

@@ -944,6 +944,14 @@ static void btstack_crypto_event_handler(uint8_t packet_type, uint16_t cid, uint
     if (packet_type != HCI_EVENT_PACKET)  return;
 
     switch (hci_event_packet_get_type(packet)){
+        case BTSTACK_EVENT_STATE:
+            log_info("BTSTACK_EVENT_STATE");
+            if (btstack_event_state_get_state(packet) != HCI_STATE_HALTING) break;
+            if (!btstack_crypto_wait_for_hci_result) break;
+            // request stack to defer shutdown a bit
+            hci_halting_defer();
+            break;
+
         case HCI_EVENT_COMMAND_COMPLETE:
     	    if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){
                 if (hci_get_state() != HCI_STATE_WORKING) return;