tests: Bluetooth: add sleep in notify cb testcase

Validates that nothing nefarious happens if the application decides to
wait an arbitrary amount of time in notification callbacks.

Also validates that a disconnection during said waiting works as
expected.

E.g. in #48505, the user was trying to send data synchronously over UART
_inside_ the notification callback. Then the device was disconnected
whilst still waiting.

This kind of pattern is not recommended, but the stack should still
function correctly, stalling the "BT RX" thread shouldn't result in
state corruption or resource leakage.

Signed-off-by: Jonathan Rico <jonathan.rico@nordicsemi.no>

tests/bsim/bluetooth/host/compile.sh

@@ -63,6 +63,8 @@ app=tests/bsim/bluetooth/host/l2cap/send_on_connect compile
 app=tests/bsim/bluetooth/host/l2cap/send_on_connect conf_file=prj_ecred.conf compile
 
 app=tests/bsim/bluetooth/host/misc/disable compile
+app=tests/bsim/bluetooth/host/misc/disconnect/dut compile
+app=tests/bsim/bluetooth/host/misc/disconnect/tester compile
 
 app=tests/bsim/bluetooth/host/privacy/central compile
 app=tests/bsim/bluetooth/host/privacy/peripheral compile

tests/bsim/bluetooth/host/misc/disconnect/common/sync.c

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/util.h>
+#include "argparse.h"
+#include "bs_types.h"
+#include "bs_tracing.h"
+#include "time_machine.h"
+#include "bstests.h"
+#include "bs_pc_backchannel.h"
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(sync, LOG_LEVEL_INF);
+
+#define CHANNEL_ID 0
+#define MSG_SIZE 1
+
+int backchannel_init(void)
+{
+	uint device_number = get_device_nbr();
+	uint peer_number = device_number ^ 1;
+	uint device_numbers[] = { peer_number };
+	uint channel_numbers[] = { CHANNEL_ID };
+	uint *ch;
+
+	ch = bs_open_back_channel(device_number, device_numbers, channel_numbers,
+				  ARRAY_SIZE(channel_numbers));
+
+	if (!ch) {
+		return -1;
+	}
+
+	return 0;
+}
+
+void backchannel_sync_send(void)
+{
+	uint8_t sync_msg[MSG_SIZE] = { get_device_nbr() };
+
+	LOG_INF("Sending sync");
+	bs_bc_send_msg(CHANNEL_ID, sync_msg, ARRAY_SIZE(sync_msg));
+}
+
+void backchannel_sync_wait(void)
+{
+	uint8_t sync_msg[MSG_SIZE];
+
+	while (true) {
+		if (bs_bc_is_msg_received(CHANNEL_ID) > 0) {
+			bs_bc_receive_msg(CHANNEL_ID, sync_msg, ARRAY_SIZE(sync_msg));
+			if (sync_msg[0] != get_device_nbr()) {
+				/* Received a message from another device, exit */
+				break;
+			}
+		}
+
+		k_sleep(K_MSEC(1));
+	}
+
+	LOG_INF("Sync received");
+}

tests/bsim/bluetooth/host/misc/disconnect/common/sync.h

@@ -0,0 +1,9 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+int backchannel_init(void);
+void backchannel_sync_send(void);
+void backchannel_sync_wait(void);

tests/bsim/bluetooth/host/misc/disconnect/common/utils.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "bs_tracing.h"
+#include "bs_types.h"
+#include "bstests.h"
+
+#define BS_SECONDS(dur_sec)    ((bs_time_t)dur_sec * USEC_PER_SEC)
+#define TEST_TIMEOUT_SIMULATED BS_SECONDS(10)
+
+extern enum bst_result_t bst_result;
+
+#define DECLARE_FLAG(flag) extern atomic_t flag
+#define DEFINE_FLAG(flag)  atomic_t flag = (atomic_t) false
+#define SET_FLAG(flag)     (void)atomic_set(&flag, (atomic_t) true)
+#define UNSET_FLAG(flag)   (void)atomic_set(&flag, (atomic_t) false)
+
+#define WAIT_FOR_EXPR(var, expr)                                                                   \
+	while (atomic_get(&var) expr) {                                                            \
+		(void)k_sleep(K_MSEC(1));                                                          \
+	}
+#define WAIT_FOR_VAL(var, val)                                                                     \
+	while (atomic_get(&var) != val) {                                                          \
+		(void)k_sleep(K_MSEC(1));                                                          \
+	}
+#define WAIT_FOR_FLAG(flag)                                                                        \
+	while (!(bool)atomic_get(&flag)) {                                                         \
+		(void)k_sleep(K_MSEC(1));                                                          \
+	}
+#define WAIT_FOR_FLAG_UNSET(flag)                                                                  \
+	while ((bool)atomic_get(&flag)) {                                                          \
+		(void)k_sleep(K_MSEC(1));                                                          \
+	}
+#define TAKE_FLAG(flag)                                                                            \
+	while (!(bool)atomic_cas(&flag, true, false)) {                                            \
+		(void)k_sleep(K_MSEC(1));                                                          \
+	}
+
+#define ASSERT(expr, ...)                                                                          \
+	do {                                                                                       \
+		if (!(expr)) {                                                                     \
+			FAIL(__VA_ARGS__);                                                         \
+		}                                                                                  \
+	} while (0)
+
+#define FAIL(...)                                                                                  \
+	do {                                                                                       \
+		bst_result = Failed;                                                               \
+		bs_trace_error_time_line(__VA_ARGS__);                                             \
+	} while (0)
+
+#define PASS(...)                                                                                  \
+	do {                                                                                       \
+		bst_result = Passed;                                                               \
+		bs_trace_info_time(1, __VA_ARGS__);                                                \
+	} while (0)
+
+#define HVX_HANDLE 0x0012
+#define INDICATION_PAYLOAD "indication"
+#define NOTIFICATION_PAYLOAD "notification"

tests/bsim/bluetooth/host/misc/disconnect/dut/CMakeLists.txt

@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(bsim_test_disconnect_dut)
+
+target_sources(app PRIVATE
+  src/main.c
+  ../common/sync.c
+)
+
+zephyr_include_directories(
+  ../common/
+  ${BSIM_COMPONENTS_PATH}/libUtilv1/src/
+  ${BSIM_COMPONENTS_PATH}/libPhyComv1/src/
+)

tests/bsim/bluetooth/host/misc/disconnect/dut/prj.conf

@@ -0,0 +1,38 @@
+CONFIG_LOG=y
+CONFIG_ASSERT=y
+
+CONFIG_BT=y
+CONFIG_BT_CENTRAL=y
+CONFIG_BT_PERIPHERAL=y
+CONFIG_BT_DEVICE_NAME="Sequential"
+
+CONFIG_BT_GATT_CLIENT=y
+CONFIG_BT_GATT_ENFORCE_SUBSCRIPTION=n
+
+# Replace `Execute` with `gdb --args` in the shell script
+# and get a nice backtrace on assert
+CONFIG_ARCH_POSIX_TRAP_ON_FATAL=y
+
+# Prepend logs with thread names
+CONFIG_THREAD_NAME=y
+CONFIG_LOG_THREAD_ID_PREFIX=y
+
+# Enable those as needed
+# CONFIG_BT_L2CAP_LOG_LEVEL_DBG=y
+# CONFIG_BT_ATT_LOG_LEVEL_DBG=y
+# CONFIG_BT_GATT_LOG_LEVEL_DBG=y
+
+# Allow whole L2CAP PDUs to fit on-air
+CONFIG_BT_BUF_ACL_TX_SIZE=251
+CONFIG_BT_BUF_ACL_RX_SIZE=251
+CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
+CONFIG_BT_DATA_LEN_UPDATE=y
+CONFIG_BT_USER_DATA_LEN_UPDATE=y
+
+# Disable auto-initiated procedures so they don't
+# mess with the test's execution.
+CONFIG_BT_AUTO_PHY_UPDATE=n
+CONFIG_BT_AUTO_DATA_LEN_UPDATE=n
+CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=n
+
+CONFIG_BT_MAX_CONN=1