Fixed deadlock in pause enable/disable

diff --git a/c/pthread_extra/pthread_pause.c b/c/pthread_extra/pthread_pause.c
index 24521af71f38741c0e85ea04412f89724f173626..f8fb296fdc7b79be4c0baa0241959d917d5e5ed0 100644 (file)
--- a/c/pthread_extra/pthread_pause.c
+++ b/c/pthread_extra/pthread_pause.c
@@ -49,9 +49,6 @@ void pthread_pause_handler(const int signal, siginfo_t *info, void *ptr) {
 void pthread_pause_enable() {
        pthread_pause_init(); //Make sure semaphore is init'd
 
-       //Add thread to internal registry
-       pthread_user_data_internal(pthread_self());
-
        //Nesting signals too deep is not good for stack
        //You can get runtime stats using following command:
        //grep -i sig /proc/$(pgrep binary)/status
@@ -71,17 +68,22 @@ void pthread_pause_enable() {
                .sa_flags = SA_SIGINFO | SA_RESTART,
                .sa_restorer = NULL
        };
+
        sigaction(PTHREAD_XSIG_STOP, &pause_sa, NULL);
 
        //Unblock signal
        pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
+
+       //Add thread to internal registry
+       pthread_user_data_internal(pthread_self()); //Only now, when signals are unblocked!
 }
 
 void pthread_pause_disable() {
+       //pthread_user_data_lock();
        pthread_pause_init(); //Make sure semaphore is init'd
 
        //Add thread to internal registry
-       pthread_user_data_internal(pthread_self());
+       //pthread_user_data_internal(pthread_self()); //DEADLOCKS!
 
        //Block signal
        sigset_t sigset;
@@ -89,9 +91,12 @@ void pthread_pause_disable() {
        sigaddset(&sigset, PTHREAD_XSIG_STOP);
 
        //Make sure all signals are dispatched before we block them
-       sem_wait(&pthread_pause_sem);
+       //Maybe not a good idea, causes DEADLOCKS!
+       //sem_wait(&pthread_pause_sem);
        pthread_sigmask(SIG_BLOCK, &sigset, NULL);
-       sem_post(&pthread_pause_sem);
+       //sem_post(&pthread_pause_sem);
+
+       //pthread_user_data_unlock();
 }
 
 /*
@@ -108,7 +113,6 @@ int pthread_pause_reschedule(pthread_t thread) {
 
 int pthread_pause_reschedule(pthread_t thread) {
        //Decide if the thread should run and signal it
-
        pthread_user_data_lock();
 
        //Wait for semaphore which means signal queue is empty
@@ -146,18 +150,20 @@ int pthread_extra_yield() {
        return pthread_yield();
 }
 
+///Pause specified thread (block until it is paused)
 int pthread_pause(pthread_t thread) {
-       //Set thread as paused and notify it via signal (wait when queue full)
        pthread_user_data_lock();
+       //Set thread as paused and notify it via signal (wait when queue full)
        pthread_user_data_internal(thread)->running = 0;
        pthread_pause_reschedule(thread);
        pthread_user_data_unlock();
        return 0;
 }
 
+///UnPause specified thread (block until it is unpaused)
 int pthread_unpause(pthread_t thread) {
-       //Set thread as running and notify it via signal (wait when queue full)
        pthread_user_data_lock();
+       //Set thread as running and notify it via signal (wait when queue full)
        pthread_user_data_internal(thread)->running = 1;
        pthread_pause_reschedule(thread);
        pthread_user_data_unlock();
@@ -204,8 +210,10 @@ void *pthread_extra_thread_wrapper(void *arg) {
        pthread_extra_wrapper_t task = *((pthread_extra_wrapper_t*)arg);
        free(arg);
 
+       pthread_pause_enable();
+
        //Register new thread to user data structure
-       pthread_user_data_internal(pthread_self()); //Perhaps already done in pthread_extra_yield()??
+       //pthread_user_data_internal(pthread_self()); //Perhaps already done in pthread_extra_yield() and pthread_pause_enable()??
 
        //TODO: user_data should do this automaticaly?
        pthread_cleanup_push(pthread_user_data_cleanup, (void *)pthread_self());

diff --git a/c/pthread_extra/test_pause.c b/c/pthread_extra/test_pause.c
index b99c388c735cc3ac0579fcace9f6cfa815a4df7f..c12de5a36bc614ff960c862601706593dc7e1b12 100644 (file)
--- a/c/pthread_extra/test_pause.c
+++ b/c/pthread_extra/test_pause.c
@@ -1,3 +1,5 @@
+#define PTHREAD_FREEWHEEL
+
 #include <signal.h>
 #include <pthread.h>
 #include <pthread_extra.h>
@@ -6,6 +8,8 @@
 #include <assert.h>
 #include <unistd.h>
 
+//#define printf(...) (0)
+
 pthread_t main_thread;
 
 void *thread_test(void *arg) {
@@ -50,20 +54,35 @@ int main() {
        while(1) {
                pthread_pause(b);
                pthread_unpause(a);
+               pthread_pause_disable();
+               pthread_pause_disable();
+               pthread_pause_disable();
                printf("SWITCH A:\n");
+               pthread_pause_enable();
+               pthread_pause_enable();
+               pthread_pause_enable();
                pthread_sleep(2);
 
+               pthread_pause_all();
                printf("SWITCH B:\n");
+               pthread_unpause_all();
                pthread_pause(a);
                pthread_unpause(b);
                pthread_sleep(2);
 
+               //pthread_pause_disable();
+               pthread_pause_all();
                printf("SWITCH A+B:\n");
+               pthread_unpause_all();
+               //pthread_pause_enable();
                pthread_unpause(a);
                pthread_unpause(b);
                pthread_sleep(1);
 
+               //pthread_pause_disable();
+               pthread_pause_all();
                printf("SWITCH MAIN ONLY:\n");
+               //pthread_pause_enable();
                pthread_pause_all();
                //printf("\n");
                pthread_sleep(1);