Author: stella.stamenova Date: Thu May 17 14:34:24 2018 New Revision: 332670
URL: http://llvm.org/viewvc/llvm-project?rev=332670&view=rev Log: [Windows, Process] Fix an issue in windows thread handling that was causing LLDB to hang Summary: The function ResumeThread on Windows returns a DWORD which is an unsigned int. In TargetThreadWindows::DoResume, there's code that determines how many times to call ResumeThread based on whether the return value is greater than 0. Since the function returns -1 (as an unsigned int) on failure, this was getting stuck in an infinite loop if ResumeThread failed for any reason. The correct thing to do is check whether the return value is -1 and then return the appropriate error instead of ignoring the return value. Reviewers: asmith, zturner, labath Reviewed By: zturner Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D47020 Modified: lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.h Modified: lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp?rev=332670&r1=332669&r2=332670&view=diff ============================================================================== --- lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp (original) +++ lldb/trunk/source/Plugins/Process/Windows/Common/ProcessWindows.cpp Thu May 17 14:34:24 2018 @@ -349,13 +349,23 @@ Status ProcessWindows::DoResume() { LLDB_LOG(log, "resuming {0} threads.", m_thread_list.GetSize()); + bool failed = false; for (uint32_t i = 0; i < m_thread_list.GetSize(); ++i) { auto thread = std::static_pointer_cast<TargetThreadWindows>( m_thread_list.GetThreadAtIndex(i)); - thread->DoResume(); + Status result = thread->DoResume(); + if (result.Fail()) { + failed = true; + LLDB_LOG(log, "Trying to resume thread at index {0}, but failed with error {1}.", i, result); + } } - SetPrivateState(eStateRunning); + if (failed) { + error.SetErrorString("ProcessWindows::DoResume failed"); + return error; + } else { + SetPrivateState(eStateRunning); + } } else { LLDB_LOG(log, "error: process %I64u is in state %u. Returning...", m_session_data->m_debugger->GetProcess().GetProcessId(), Modified: lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp?rev=332670&r1=332669&r2=332670&view=diff ============================================================================== --- lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp (original) +++ lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp Thu May 17 14:34:24 2018 @@ -98,11 +98,11 @@ Unwind *TargetThreadWindows::GetUnwinder return m_unwinder_ap.get(); } -bool TargetThreadWindows::DoResume() { +Status TargetThreadWindows::DoResume() { StateType resume_state = GetTemporaryResumeState(); StateType current_state = GetState(); if (resume_state == current_state) - return true; + return Status(); if (resume_state == eStateStepping) { uint32_t flags_index = @@ -118,8 +118,16 @@ bool TargetThreadWindows::DoResume() { DWORD previous_suspend_count = 0; HANDLE thread_handle = m_host_thread.GetNativeThread().GetSystemHandle(); do { + // ResumeThread returns -1 on error, or the thread's *previous* suspend count on success. + // This means that the return value is 1 when the thread was restarted. + // Note that DWORD is an unsigned int, so we need to explicitly compare with -1. previous_suspend_count = ::ResumeThread(thread_handle); - } while (previous_suspend_count > 0); + + if (previous_suspend_count == (DWORD)-1) + return Status(::GetLastError(), eErrorTypeWin32); + + } while (previous_suspend_count > 1); } - return true; + + return Status(); } Modified: lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.h URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.h?rev=332670&r1=332669&r2=332670&view=diff ============================================================================== --- lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.h (original) +++ lldb/trunk/source/Plugins/Process/Windows/Common/TargetThreadWindows.h Thu May 17 14:34:24 2018 @@ -37,7 +37,7 @@ public: bool CalculateStopInfo() override; Unwind *GetUnwinder() override; - bool DoResume(); + Status DoResume(); HostThread GetHostThread() const { return m_host_thread; } _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
