debug: Disable "at exit" LSAN leak check

Disable "at exit" memory leak check by LSAN if building for a 64-bit
target with GCC. This is need to fix a potential deadlock in GCCs
libasan implementation.

Fixes #20122

Signed-off-by: Jan Van Winkel <jan.van_winkel@dxplore.eu>

subsys/debug/CMakeLists.txt

@@ -5,4 +5,9 @@ zephyr_sources_ifdef(
   openocd.c
   )
 
+zephyr_sources_ifdef(
+  CONFIG_ASAN
+  asan.c
+  )
+
 add_subdirectory(tracing)

subsys/debug/Kconfig

@@ -52,6 +52,11 @@ config ASAN
 	  recent-ish compiler with the ``-fsanitize=address`` command line option,
 	  and the libasan library.
 
+	  Note that at exit leak detection is disabled for 64-bit boards when
+	  GCC is used due to potential risk of a deadlock in libasan.
+	  This behavior can be changes by adding leak_check_at_exit=1 to the
+	  environment variable ASAN_OPTIONS.
+
 config UBSAN
 	bool "Build with undefined behavior sanitizer"
 	depends on ARCH_POSIX

subsys/debug/asan.c

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2019 Jan Van Winkel <jan.van_winkel@dxplore.eu>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+const char *__asan_default_options(void)
+{
+	return
+#if defined(CONFIG_64BIT) && defined(__GNUC__) && !defined(__clang__)
+		/* Running leak detection at exit could lead to a deadlock on
+		 * 64-bit boards if GCC is used.
+		 * https://github.com/zephyrproject-rtos/zephyr/issues/20122
+		 */
+		"leak_check_at_exit=0:"
+#endif
+		"";
+}