Fix Lua scripting synchronization

For several years now, the lua script lock has been completely broken.
This commit fixes the main issue (creation of a temporary rather than
scoped object), and fixes a subsequent deadlock issue caused by
nested script API calls by adding support for recursive mutexes.
master
kwolekr 2015-10-31 16:31:43 -04:00
parent d198e420ec
commit 52e5b513ed
5 changed files with 57 additions and 17 deletions

View File

@ -67,10 +67,11 @@ public:
ScriptApiBase
*/
ScriptApiBase::ScriptApiBase()
ScriptApiBase::ScriptApiBase() :
m_luastackmutex(true)
{
#ifdef SCRIPTAPI_LOCK_DEBUG
m_locked = false;
m_lock_recursion_count = 0;
#endif
m_luastack = luaL_newstate();
@ -157,9 +158,14 @@ void ScriptApiBase::loadScript(const std::string &script_path)
// - runs the callbacks
// - replaces the table and arguments with the return value,
// computed depending on mode
// This function must only be called with scriptlock held (i.e. inside of a
// code block with SCRIPTAPI_PRECHECKHEADER declared)
void ScriptApiBase::runCallbacksRaw(int nargs,
RunCallbacksMode mode, const char *fxn)
{
#ifdef SCRIPTAPI_LOCK_DEBUG
assert(m_lock_recursion_count > 0);
#endif
lua_State *L = getStack();
FATAL_ERROR_IF(lua_gettop(L) < nargs + 1, "Not enough arguments");

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@ -28,6 +28,7 @@ extern "C" {
}
#include "irrlichttypes.h"
#include "threads.h"
#include "threading/mutex.h"
#include "threading/mutex_auto_lock.h"
#include "common/c_types.h"
@ -111,7 +112,8 @@ protected:
std::string m_last_run_mod;
bool m_secure;
#ifdef SCRIPTAPI_LOCK_DEBUG
bool m_locked;
int m_lock_recursion_count;
threadid_t m_owning_thread;
#endif
private:

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@ -32,28 +32,50 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#ifdef SCRIPTAPI_LOCK_DEBUG
#include "debug.h" // assert()
class LockChecker {
public:
LockChecker(bool *variable) {
assert(*variable == false);
LockChecker(int *recursion_counter, threadid_t *owning_thread)
{
m_lock_recursion_counter = recursion_counter;
m_owning_thread = owning_thread;
m_original_level = *recursion_counter;
m_variable = variable;
*m_variable = true;
if (*m_lock_recursion_counter > 0)
assert(thr_is_current_thread(*m_owning_thread));
else
*m_owning_thread = thr_get_current_thread_id();
(*m_lock_recursion_counter)++;
}
~LockChecker() {
*m_variable = false;
~LockChecker()
{
assert(thr_is_current_thread(*m_owning_thread));
assert(*m_lock_recursion_counter > 0);
(*m_lock_recursion_counter)--;
assert(*m_lock_recursion_counter == m_original_level);
}
private:
bool *m_variable;
int *m_lock_recursion_counter;
int m_original_level;
threadid_t *m_owning_thread;
};
#define SCRIPTAPI_LOCK_CHECK LockChecker(&(this->m_locked))
#define SCRIPTAPI_LOCK_CHECK \
LockChecker scriptlock_checker( \
&this->m_lock_recursion_count, \
&this->m_owning_thread)
#else
#define SCRIPTAPI_LOCK_CHECK while(0)
#define SCRIPTAPI_LOCK_CHECK while(0)
#endif
#define SCRIPTAPI_PRECHECKHEADER \
MutexAutoLock(this->m_luastackmutex); \
MutexAutoLock scriptlock(this->m_luastackmutex); \
SCRIPTAPI_LOCK_CHECK; \
realityCheck(); \
lua_State *L = getStack(); \

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@ -34,15 +34,25 @@ DEALINGS IN THE SOFTWARE.
#define UNUSED(expr) do { (void)(expr); } while (0)
Mutex::Mutex()
Mutex::Mutex(bool recursive)
{
#ifdef _WIN32
// Windows critical sections are recursive by default
UNUSED(recursive);
InitializeCriticalSection(&mutex);
#else
int ret = pthread_mutex_init(&mutex, NULL);
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
if (recursive)
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
int ret = pthread_mutex_init(&mutex, &attr);
assert(!ret);
UNUSED(ret);
pthread_mutexattr_destroy(&attr);
#endif
}

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@ -49,7 +49,7 @@ DEALINGS IN THE SOFTWARE.
class Mutex
{
public:
Mutex();
Mutex(bool recursive=false);
~Mutex();
void lock();
void unlock();