[Qemu-devel] [PATCH] thread-win32: fix GetThreadContext() permanently fails

[Zavadovsky Yan]

Calling SuspendThread() is not enough to suspend Win32 thread.
We need to call GetThreadContext() after SuspendThread()
to make sure that OS have really suspended target thread.
But GetThreadContext() needs for THREAD_GET_CONTEXT
access right on thread object.

This patch adds THREAD_GET_CONTEXT to OpenThread() arguments
and change 'while(GetThreadContext() == SUCCESS)' to
'while(GetThreadContext() == FAILED)'.
So this 'while' loop will stop only after successful grabbing
of thread context(i.e. when thread is really suspended).
Not after the one failed GetThreadContext() call.

Signed-off-by: Zavadovsky Yan <address@hidden>
---
 cpus.c                   | 2 +-
 util/qemu-thread-win32.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/cpus.c b/cpus.c
index b85fb5f..83d5eb5 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1097,7 +1097,7 @@ static void qemu_cpu_kick_thread(CPUState *cpu)
          * suspended until we can get the context.
          */
         tcgContext.ContextFlags = CONTEXT_CONTROL;
-        while (GetThreadContext(cpu->hThread, &tcgContext) != 0) {
+        while (GetThreadContext(cpu->hThread, &tcgContext) == 0) {
             continue;
         }
 
diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
index 406b52f..823eca1 100644
--- a/util/qemu-thread-win32.c
+++ b/util/qemu-thread-win32.c
@@ -406,8 +406,8 @@ HANDLE qemu_thread_get_handle(QemuThread *thread)
 
     EnterCriticalSection(&data->cs);
     if (!data->exited) {
-        handle = OpenThread(SYNCHRONIZE | THREAD_SUSPEND_RESUME, FALSE,
-                            thread->tid);
+        handle = OpenThread(SYNCHRONIZE | THREAD_SUSPEND_RESUME | 
THREAD_GET_CONTEXT,
+                            FALSE, thread->tid);
     } else {
         handle = NULL;
     }
-- 
2.4.4.windows.2