From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43470) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7jkx-0004Fz-8o for qemu-devel@nongnu.org; Wed, 24 Jun 2015 08:26:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z7jks-0006ZH-W7 for qemu-devel@nongnu.org; Wed, 24 Jun 2015 08:26:19 -0400 Received: from mail-lb0-x22d.google.com ([2a00:1450:4010:c04::22d]:35928) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7jks-0006Yg-N3 for qemu-devel@nongnu.org; Wed, 24 Jun 2015 08:26:14 -0400 Received: by lbbpo10 with SMTP id po10so25251402lbb.3 for ; Wed, 24 Jun 2015 05:26:13 -0700 (PDT) From: Zavadovsky Yan Date: Wed, 24 Jun 2015 15:25:53 +0300 Message-Id: <1435148753-4476-1-git-send-email-zavadovsky.yan@gmail.com> Subject: [Qemu-devel] [PATCH v2] thread-win32: fix GetThreadContext() permanently fails List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: hainque@adacore.com, peter.maydell@linaro.org, zavadovsky.yan@gmail.com, sw@weilnetz.de, chouteau@adacore.com, pbonzini@redhat.com 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. More info about this technique can be found here: http://blogs.msdn.com/b/oldnewthing/archive/2015/02/05/10591215.aspx This patch adds THREAD_GET_CONTEXT to OpenThread() arguments and change oddity 'while(GetThreadContext() == SUCCESS)' to 'if(GetThreadContext() == FAILED){exit(1);}'. So this block of code will continue only after successful grabbing of thread context(i.e. when thread is really suspended). And halts otherwise with more verbose error message than previous. Signed-off-by: Zavadovsky Yan --- cpus.c | 14 ++++++++------ util/qemu-thread-win32.c | 4 ++-- 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/cpus.c b/cpus.c index 4f0e54d..0df6a7d 100644 --- a/cpus.c +++ b/cpus.c @@ -1089,8 +1089,8 @@ static void qemu_cpu_kick_thread(CPUState *cpu) CONTEXT tcgContext; if (SuspendThread(cpu->hThread) == (DWORD)-1) { - fprintf(stderr, "qemu:%s: GetLastError:%lu\n", __func__, - GetLastError()); + fprintf(stderr, "qemu:%s: SuspendThread GetLastError:%lu\n", + __func__, GetLastError()); exit(1); } @@ -1098,15 +1098,17 @@ 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) { - continue; + if (GetThreadContext(cpu->hThread, &tcgContext) == 0) { + fprintf(stderr, "qemu:%s: GetThreadContext GetLastError:%lu\n", + __func__, GetLastError()); + exit(1); } cpu_signal(0); if (ResumeThread(cpu->hThread) == (DWORD)-1) { - fprintf(stderr, "qemu:%s: GetLastError:%lu\n", __func__, - GetLastError()); + fprintf(stderr, "qemu:%s: ResumeThread GetLastError:%lu\n", + __func__, GetLastError()); exit(1); } } 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