Author: gclayton
Date: Thu Dec 8 19:21:14 2016
New Revision: 289169
URL: http://llvm.org/viewvc/llvm-project?rev=289169&view=rev
Log:
Calling SBDebugger::CeeateTarget being called on multiple threads was crashing
LLDB.
I found the race condition in:
ScriptInterpreter *CommandInterpreter::GetScriptInterpreter(bool can_create);
More than one "ScriptInterpreter *" was being returned due to the race which
caused any clients with the first one to now be pointing to freed memory and we
would quickly crash.
Added a test to catch this so we don't regress.
<rdar://problem/28356584>
Added:
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/Makefile
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp
Modified:
lldb/trunk/include/lldb/Interpreter/CommandInterpreter.h
lldb/trunk/source/Interpreter/CommandInterpreter.cpp
Modified: lldb/trunk/include/lldb/Interpreter/CommandInterpreter.h
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Interpreter/CommandInterpreter.h?rev=289169&r1=289168&r2=289169&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Interpreter/CommandInterpreter.h (original)
+++ lldb/trunk/include/lldb/Interpreter/CommandInterpreter.h Thu Dec 8
19:21:14 2016
@@ -12,6 +12,7 @@
// C Includes
// C++ Includes
+#include <mutex>
// Other libraries and framework includes
// Project includes
#include "lldb/Core/Broadcaster.h"
@@ -538,6 +539,7 @@ private:
std::string m_repeat_command; // Stores the command that will be executed for
// an empty command string.
lldb::ScriptInterpreterSP m_script_interpreter_sp;
+ std::mutex m_script_interpreter_mutex;
lldb::IOHandlerSP m_command_io_handler_sp;
char m_comment_char;
bool m_batch_command_mode;
Added: lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/Makefile
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/Makefile?rev=289169&view=auto
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/Makefile
(added)
+++ lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/Makefile Thu
Dec 8 19:21:14 2016
@@ -0,0 +1,8 @@
+LEVEL = ../../make
+
+MAKE_DSYM := NO
+
+ENABLE_THREADS := YES
+CXX_SOURCES := main.cpp
+
+include $(LEVEL)/Makefile.rules
Added:
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py?rev=289169&view=auto
==============================================================================
---
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py
(added)
+++
lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/TestMultipleTargets.py
Thu Dec 8 19:21:14 2016
@@ -0,0 +1,39 @@
+"""Test the lldb public C++ api when creating multiple targets
simultaneously."""
+
+from __future__ import print_function
+
+
+import os
+import re
+import subprocess
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestMultipleSimultaneousDebuggers(TestBase):
+
+ mydir = TestBase.compute_mydir(__file__)
+
+ @skipIfNoSBHeaders
+ def test_multiple_debuggers(self):
+ env = {self.dylibPath: self.getLLDBLibraryEnvVal()}
+
+ self.driver_exe = os.path.join(os.getcwd(), "multi-target")
+ self.buildDriver('main.cpp', self.driver_exe)
+ self.addTearDownHook(lambda: os.remove(self.driver_exe))
+ self.signBinary(self.driver_exe)
+
+# check_call will raise a CalledProcessError if multi-process-driver doesn't
return
+# exit code 0 to indicate success. We can let this exception go - the test
harness
+# will recognize it as a test failure.
+
+ if self.TraceOn():
+ print("Running test %s" % self.driver_exe)
+ check_call([self.driver_exe, self.driver_exe], env=env)
+ else:
+ with open(os.devnull, 'w') as fnull:
+ check_call([self.driver_exe, self.driver_exe],
+ env=env, stdout=fnull, stderr=fnull)
Added: lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp?rev=289169&view=auto
==============================================================================
--- lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp
(added)
+++ lldb/trunk/packages/Python/lldbsuite/test/api/multiple-targets/main.cpp Thu
Dec 8 19:21:14 2016
@@ -0,0 +1,31 @@
+#include <thread>
+
+#include "lldb/API/LLDB.h"
+#include "lldb/API/SBDebugger.h"
+#include "lldb/API/SBTarget.h"
+
+using namespace lldb;
+int main (int argc, char **argv)
+{
+ // We are expecting the program path and a path to an executable to load
+ if (argc != 2)
+ return 1;
+ const char *program_file = argv[1];
+ SBDebugger::Initialize();
+ SBDebugger debugger = SBDebugger::Create(false);
+ auto lambda = [&](){
+ SBError error;
+ SBTarget target = debugger.CreateTarget(program_file, nullptr, nullptr,
+ false, error);
+ };
+
+ // Create 3 targets at the same time and make sure we don't crash.
+ std::thread thread1(lambda);
+ std::thread thread2(lambda);
+ std::thread thread3(lambda);
+ thread1.join();
+ thread2.join();
+ thread3.join();
+ SBDebugger::Terminate();
+ return 0;
+}
Modified: lldb/trunk/source/Interpreter/CommandInterpreter.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Interpreter/CommandInterpreter.cpp?rev=289169&r1=289168&r2=289169&view=diff
==============================================================================
--- lldb/trunk/source/Interpreter/CommandInterpreter.cpp (original)
+++ lldb/trunk/source/Interpreter/CommandInterpreter.cpp Thu Dec 8 19:21:14
2016
@@ -2477,15 +2477,14 @@ void CommandInterpreter::HandleCommandsF
}
ScriptInterpreter *CommandInterpreter::GetScriptInterpreter(bool can_create) {
- if (m_script_interpreter_sp)
- return m_script_interpreter_sp.get();
-
- if (!can_create)
- return nullptr;
-
- lldb::ScriptLanguage script_lang = GetDebugger().GetScriptLanguage();
- m_script_interpreter_sp =
- PluginManager::GetScriptInterpreterForLanguage(script_lang, *this);
+ std::lock_guard<std::mutex> locker(m_script_interpreter_mutex);
+ if (!m_script_interpreter_sp) {
+ if (!can_create)
+ return nullptr;
+ lldb::ScriptLanguage script_lang = GetDebugger().GetScriptLanguage();
+ m_script_interpreter_sp =
+ PluginManager::GetScriptInterpreterForLanguage(script_lang, *this);
+ }
return m_script_interpreter_sp.get();
}
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