[utils] Improve error message in case of thread suspend fails.

diff --git a/mono/utils/mono-threads.c b/mono/utils/mono-threads.c
index 0258e2aa28fc31ca3e7556c2588dcd8aad0b6b74..228f611bf72fffbd6c331655874072e5c9a07e42 100644 (file)
--- a/mono/utils/mono-threads.c
+++ b/mono/utils/mono-threads.c
@@ -357,18 +357,21 @@ mono_threads_get_runtime_callbacks (void)
 The return value is only valid until a matching mono_thread_info_resume is called
 */
 static MonoThreadInfo*
-mono_thread_info_suspend_sync (MonoNativeThreadId tid, gboolean interrupt_kernel)
+mono_thread_info_suspend_sync (MonoNativeThreadId tid, gboolean interrupt_kernel, const char **error_condition)
 {
        MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();      
        MonoThreadInfo *info = mono_thread_info_lookup (tid); /*info on HP1*/
-       if (!info)
+       if (!info) {
+               *error_condition = "Thread not found";
                return NULL;
+       }
 
        MONO_SEM_WAIT_UNITERRUPTIBLE (&info->suspend_semaphore);
 
        /*thread is on the process of detaching*/
        if (mono_thread_info_run_state (info) > STATE_RUNNING) {
                mono_hazard_pointer_clear (hp, 1);
+               *error_condition = "Thread is detaching";
                return NULL;
        }
 
@@ -384,6 +387,7 @@ mono_thread_info_suspend_sync (MonoNativeThreadId tid, gboolean interrupt_kernel
        if (!mono_threads_core_suspend (info)) {
                MONO_SEM_POST (&info->suspend_semaphore);
                mono_hazard_pointer_clear (hp, 1);
+               *error_condition = "Could not suspend thread";
                return NULL;
        }
 
@@ -557,8 +561,9 @@ mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_ke
        mono_thread_info_suspend_lock ();
 
        for (;;) {
-               if (!(info = mono_thread_info_suspend_sync (id, interrupt_kernel))) {
-                       g_warning ("failed to suspend thread %p, hopefully it is dead", (gpointer)id);
+               const char *suspend_error = "Unknown error";
+               if (!(info = mono_thread_info_suspend_sync (id, interrupt_kernel, &suspend_error))) {
+                       g_warning ("failed to suspend thread %p due to %s, hopefully it is dead", (gpointer)id, suspend_error);
                        mono_thread_info_suspend_unlock ();
                        return NULL;
                }
@@ -567,7 +572,7 @@ mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_ke
                        break;
 
                if (!mono_thread_info_core_resume (info)) {
-                       g_warning ("failed to result thread %p, hopefully it is dead", (gpointer)id);
+                       g_warning ("failed to resume thread %p, hopefully it is dead", (gpointer)id);
                        mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
                        mono_thread_info_suspend_unlock ();
                        return NULL;