From 3f06210295051a413473e8f7d2b4a299c1f04635 Mon Sep 17 00:00:00 2001 From: Adrian McCarthy Date: Mon, 22 Jul 2019 17:03:20 +0000 Subject: [PATCH] [Windows] Fix race condition between state changes Patch by Martin Andersson (martin.andersson@evoma.se) If the process is resumed before the state is changed to "running" there is a possibility (when single stepping) that the debugger stops and changes the state to "stopped" before it is first changed to "running". This causes the process to ignore the stop event (since the state did not change) which in turn leads the DebuggerThread to wait indefinitely for the exception predicate in HandleExceptionEvent. Differential Revision: https://reviews.llvm.org/D62183 llvm-svn: 366703 --- .../Process/Windows/Common/ProcessWindows.cpp | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 49801fe..7303e17 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -205,16 +205,6 @@ Status ProcessWindows::DoResume() { m_session_data->m_debugger->GetProcess().GetProcessId(), GetPrivateState()); - ExceptionRecordSP active_exception = - m_session_data->m_debugger->GetActiveException().lock(); - if (active_exception) { - // Resume the process and continue processing debug events. Mask the - // exception so that from the process's view, there is no indication that - // anything happened. - m_session_data->m_debugger->ContinueAsyncException( - ExceptionResult::MaskException); - } - LLDB_LOG(log, "resuming {0} threads.", m_thread_list.GetSize()); bool failed = false; @@ -233,10 +223,19 @@ Status ProcessWindows::DoResume() { if (failed) { error.SetErrorString("ProcessWindows::DoResume failed"); - return error; } else { SetPrivateState(eStateRunning); } + + ExceptionRecordSP active_exception = + m_session_data->m_debugger->GetActiveException().lock(); + if (active_exception) { + // Resume the process and continue processing debug events. Mask the + // exception so that from the process's view, there is no indication that + // anything happened. + m_session_data->m_debugger->ContinueAsyncException( + ExceptionResult::MaskException); + } } else { LLDB_LOG(log, "error: process {0} is in state {1}. Returning...", m_session_data->m_debugger->GetProcess().GetProcessId(), -- 2.7.4