From 1085a394a4093baf33a5be6fcf2494cd2eb2fa8c Mon Sep 17 00:00:00 2001
From: Thays Grazia <thaystg@gmail.com>
Date: Wed, 25 Sep 2019 17:12:33 -0300
Subject: [PATCH] [threading] embedded mono hangs (mono/mono#16907)

* [threading] embedded mono hangs

When embedded mono is executing a C++ code, it didn't start to execute a C# code, we don't need to suspend the thread to run GC.
Fixes mono/mono#16192
Fixes mono/mono#14725

* Changing what was discussed with Aleksey during our 1on1

* Changing what was suggested by Aleksey

* Separating mono_init_version that is being used on tests from the embedded ones


Commit migrated from https://github.com/mono/mono/commit/5b108b5726ec196f4b61d30f406919ce70211754
---
 src/mono/mono/mini/driver.c                   | 15 +++++++++++++--
 src/mono/mono/mini/jit.h                      |  7 +++++--
 src/mono/mono/unit-tests/test-mono-callspec.c |  2 +-
 src/mono/mono/unit-tests/test-mono-string.c   |  2 +-
 src/mono/mono/utils/mono-threads-api.h        |  7 +------
 5 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/mono/mono/mini/driver.c b/src/mono/mono/mini/driver.c
index f5d41bb..06db626 100644
--- a/src/mono/mono/mini/driver.c
+++ b/src/mono/mono/mini/driver.c
@@ -2754,7 +2754,9 @@ mono_main (int argc, char* argv[])
 MonoDomain * 
 mono_jit_init (const char *file)
 {
-	return mini_init (file, NULL);
+	MonoDomain *ret = mini_init (file, NULL);
+	MONO_ENTER_GC_SAFE_UNBALANCED; //once it is not executing any managed code yet, it's safe to run the gc
+	return ret;
 }
 
 /**
@@ -2780,7 +2782,16 @@ mono_jit_init (const char *file)
 MonoDomain * 
 mono_jit_init_version (const char *domain_name, const char *runtime_version)
 {
-	return mini_init (domain_name, runtime_version);
+	MonoDomain *ret = mini_init (domain_name, runtime_version);
+	MONO_ENTER_GC_SAFE_UNBALANCED; //once it is not executing any managed code yet, it's safe to run the gc
+	return ret;
+}
+
+MonoDomain * 
+mono_jit_init_version_for_test_only (const char *domain_name, const char *runtime_version)
+{
+	MonoDomain *ret = mini_init (domain_name, runtime_version);
+	return ret;
 }
 
 /**
diff --git a/src/mono/mono/mini/jit.h b/src/mono/mono/mini/jit.h
index 2ada49b..9fc6a18 100644
--- a/src/mono/mono/mini/jit.h
+++ b/src/mono/mono/mini/jit.h
@@ -13,12 +13,15 @@
 
 MONO_BEGIN_DECLS
 
-MONO_API MonoDomain * 
+MONO_API MONO_RT_EXTERNAL_ONLY MonoDomain * 
 mono_jit_init              (const char *file);
 
-MONO_API MonoDomain * 
+MONO_API MONO_RT_EXTERNAL_ONLY MonoDomain * 
 mono_jit_init_version      (const char *root_domain_name, const char *runtime_version);
 
+MONO_API MonoDomain * 
+mono_jit_init_version_for_test_only      (const char *root_domain_name, const char *runtime_version);
+
 MONO_API int
 mono_jit_exec              (MonoDomain *domain, MonoAssembly *assembly, 
 			    int argc, char *argv[]);
diff --git a/src/mono/mono/unit-tests/test-mono-callspec.c b/src/mono/mono/unit-tests/test-mono-callspec.c
index 30b6900..186286c 100644
--- a/src/mono/mono/unit-tests/test-mono-callspec.c
+++ b/src/mono/mono/unit-tests/test-mono-callspec.c
@@ -192,7 +192,7 @@ test_mono_callspec_main (void)
 		goto out;
 	}
 
-	domain = mono_jit_init_version ("TEST RUNNER", "mobile");
+	domain = mono_jit_init_version_for_test_only ("TEST RUNNER", "mobile");
 	assembly = mono_assembly_open (TESTPROG, &status);
 	if (!domain || !assembly) {
 		res = 1;
diff --git a/src/mono/mono/unit-tests/test-mono-string.c b/src/mono/mono/unit-tests/test-mono-string.c
index 4edda5f..b545486 100644
--- a/src/mono/mono/unit-tests/test-mono-string.c
+++ b/src/mono/mono/unit-tests/test-mono-string.c
@@ -59,7 +59,7 @@ int
 test_mono_string_main (void)
 {
 
-	mono_jit_init_version ("test-mono-string", "v4.0.30319");
+	mono_jit_init_version_for_test_only ("test-mono-string", "v4.0.30319");
 
 	int res = 0;
 
diff --git a/src/mono/mono/utils/mono-threads-api.h b/src/mono/mono/utils/mono-threads-api.h
index c8e3410..8315b0c 100644
--- a/src/mono/mono/utils/mono-threads-api.h
+++ b/src/mono/mono/utils/mono-threads-api.h
@@ -130,13 +130,8 @@ http://www.mono-project.com/docs/advanced/runtime/docs/coop-suspend/#gc-unsafe-m
 	} while (0)
 
 #define MONO_ENTER_GC_SAFE_UNBALANCED	\
-	do {	\
 		MONO_STACKDATA (__gc_safe_unbalanced_dummy); \
-		gpointer __gc_safe_unbalanced_cookie = mono_threads_enter_gc_safe_region_unbalanced_internal (&__gc_safe_unbalanced_dummy)
-
-#define MONO_EXIT_GC_SAFE_UNBALANCED	\
-		mono_threads_exit_gc_safe_region_unbalanced_internal (__gc_safe_unbalanced_cookie, &__gc_safe_unbalanced_dummy);	\
-	} while (0)
+		mono_threads_enter_gc_safe_region_unbalanced_internal (&__gc_safe_unbalanced_dummy)
 
 void
 mono_threads_enter_no_safepoints_region (const char *func);
-- 
2.7.4