fix very annoying recursive mutex + pthread cond bug reported by setatg, Waldorf, and many others

libtransmission/fdlimit.c

@@ -109,7 +109,6 @@ struct tr_fd_s
     int                  normal;
     int                  normalMax;
     tr_lock            * lock;
-    tr_cond            * cond;
     struct tr_openfile   open[TR_MAX_OPEN_FILES];
 };
 
@@ -180,7 +179,6 @@ TrCloseFile( int i )
     close( o->fd );
     o->fd = -1;
     o->isCheckedOut = 0;
-    tr_condSignal( gFd->cond );
 }
 
 static int
@@ -215,7 +213,7 @@ tr_fdFileCheckout( const char * filename, int write )
 
         if( fileIsCheckedOut( o ) ) {
             dbgmsg( "found it!  it's open, but checked out.  waiting..." );
-            tr_condWait( gFd->cond, gFd->lock );
+            tr_wait( 100 );
             i = -1; /* reloop */
             continue;
         }
@@ -262,7 +260,7 @@ tr_fdFileCheckout( const char * filename, int write )
 
         /* All used! Wait a bit and try again */
         dbgmsg( "everything's full!  waiting for someone else to finish something" );
-        tr_condWait( gFd->cond, gFd->lock );
+        tr_wait( 100 );
     }
 
 done:
@@ -309,7 +307,6 @@ tr_fdFileReturn( int fd )
         break;
     }
     
-    tr_condSignal( gFd->cond );
     tr_lockUnlock( gFd->lock );
 }
 
@@ -335,7 +332,6 @@ tr_fdFileClose( const char * filename )
         }
     }
     
-    tr_condSignal( gFd->cond );
     tr_lockUnlock( gFd->lock );
 }
 
@@ -462,7 +458,6 @@ tr_fdInit( void )
 
     gFd = tr_new0( struct tr_fd_s, 1 );
     gFd->lock = tr_lockNew( );
-    gFd->cond = tr_condNew( );
 
     /* count the max number of sockets we can use */
     for( i=0; i<TR_MAX_SOCKETS; ++i )
@@ -490,7 +485,6 @@ tr_fdClose( void )
             TrCloseFile( i );
 
     tr_lockFree( gFd->lock );
-    tr_condFree( gFd->cond );
 
     tr_list_free( &reservedSockets, NULL );
     tr_free( gFd );

libtransmission/platform.c

@@ -248,10 +248,11 @@ tr_lockLock( tr_lock * l )
 #else
     pthread_mutex_lock( &l->lock );
 #endif
+    assert( l->depth >= 0 );
+    if( l->depth )
+        assert( tr_areThreadsEqual( l->lockThread, tr_getCurrentThread() ) );
     l->lockThread = tr_getCurrentThread( );
     ++l->depth;
-/* fprintf( stderr, "thread %lu acquired lock %p... depth is now %d\n", (unsigned long)l->lockThread, l, l->depth ); */
-    assert( l->depth >= 1 );
 }
 
 int
@@ -264,11 +265,8 @@ tr_lockHave( const tr_lock * l )
 void
 tr_lockUnlock( tr_lock * l )
 {
-/* fprintf( stderr, "thread %lu releasing lock %p... depth before release is %d\n", (unsigned long)l->lockThread, l, l->depth ); */
-
     assert( l->depth > 0 );
     assert( tr_areThreadsEqual( l->lockThread, tr_getCurrentThread() ));
-    assert( tr_lockHave( l ) );
 
     --l->depth;
     assert( l->depth >= 0 );
@@ -281,188 +279,6 @@ tr_lockUnlock( tr_lock * l )
 #endif
 }
 
-/***
-****  COND
-***/
-
-struct tr_cond
-{
-#ifdef __BEOS__
-    sem_id sem;
-    thread_id threads[BEOS_MAX_THREADS];
-    int start, end;
-#elif defined(WIN32)
-    tr_list * events;
-    tr_lock * lock;
-#else
-    pthread_cond_t cond;
-#endif
-};
-
-#ifdef WIN32
-static DWORD getContEventTLS( void )
-{
-    static int inited = FALSE;
-    static DWORD event_tls;
-    if( !inited ) {
-        inited = TRUE;
-        event_tls = TlsAlloc();
-    }
-    return event_tls;
-}
-#endif
-
-tr_cond*
-tr_condNew( void )
-{
-    tr_cond * c = tr_new0( tr_cond, 1 );
-#ifdef __BEOS__
-    c->sem = create_sem( 1, "" );
-    c->start = 0;
-    c->end = 0;
-#elif defined(WIN32)
-    c->events = NULL;
-    c->lock = tr_lockNew( );
-#else
-    pthread_cond_init( &c->cond, NULL );
-#endif
-    return c;
-}
-
-void
-tr_condWait( tr_cond * c, tr_lock * l )
-{
-#ifdef __BEOS__
-
-    /* Keep track of that thread */
-    acquire_sem( c->sem );
-    c->threads[c->end] = find_thread( NULL );
-    c->end = ( c->end + 1 ) % BEOS_MAX_THREADS;
-    assert( c->end != c->start ); /* We hit BEOS_MAX_THREADS, arggh */
-    release_sem( c->sem );
-
-    release_sem( l->lock );
-    suspend_thread( find_thread( NULL ) ); /* Wait for signal */
-    acquire_sem( l->lock );
-
-#elif defined(WIN32)
-
-    /* get this thread's cond event */
-    DWORD key = getContEventTLS ( );
-    HANDLE hEvent = TlsGetValue( key );
-    if( !hEvent ) {
-        hEvent = CreateEvent( 0, FALSE, FALSE, 0 );
-        TlsSetValue( key, hEvent );
-    }
-
-    /* add it to the list of events waiting to be signaled */
-    tr_lockLock( c->lock );
-    tr_list_append( &c->events, hEvent );
-    tr_lockUnlock( c->lock );
-
-    /* now wait for it to be signaled */
-    tr_lockUnlock( l );
-    WaitForSingleObject( hEvent, INFINITE );
-    tr_lockLock( l );
-
-    /* remove it from the list of events waiting to be signaled */
-    tr_lockLock( c->lock );
-    tr_list_remove_data( &c->events, hEvent );
-    tr_lockUnlock( c->lock );
-
-#else
-
-    pthread_cond_wait( &c->cond, &l->lock );
-
-#endif
-}
-
-#ifdef __BEOS__
-static int condTrySignal( tr_cond * c )
-{
-    if( c->start == c->end )
-        return 1;
-
-    for( ;; )
-    {
-        thread_info info;
-        get_thread_info( c->threads[c->start], &info );
-        if( info.state == B_THREAD_SUSPENDED )
-        {
-            resume_thread( c->threads[c->start] );
-            c->start = ( c->start + 1 ) % BEOS_MAX_THREADS;
-            break;
-        }
-        /* The thread is not suspended yet, which can happen since
-         * tr_condWait does not atomically suspends after releasing
-         * the semaphore. Wait a bit and try again. */
-        snooze( 5000 );
-    }
-    return 0;
-}
-#endif
-void
-tr_condSignal( tr_cond * c )
-{
-#ifdef __BEOS__
-
-    acquire_sem( c->sem );
-    condTrySignal( c );
-    release_sem( c->sem );
-
-#elif defined(WIN32)
-
-    tr_lockLock( c->lock );
-    if( c->events != NULL )
-        SetEvent( (HANDLE)c->events->data );
-    tr_lockUnlock( c->lock );
-
-#else
-
-    pthread_cond_signal( &c->cond );
-
-#endif
-}
-
-void
-tr_condBroadcast( tr_cond * c )
-{
-#ifdef __BEOS__
-
-    acquire_sem( c->sem );
-    while( !condTrySignal( c ) );
-    release_sem( c->sem );
-
-#elif defined(WIN32)
-
-    tr_list * l;
-    tr_lockLock( c->lock );
-    for( l=c->events; l!=NULL; l=l->next )
-        SetEvent( (HANDLE)l->data );
-    tr_lockUnlock( c->lock );
-
-#else
-
-    pthread_cond_broadcast( &c->cond );
-
-#endif
-}
-
-void
-tr_condFree( tr_cond * c )
-{
-#ifdef __BEOS__
-    delete_sem( c->sem );
-#elif defined(WIN32)
-    tr_list_free( &c->events, NULL );
-    tr_lockFree( c->lock );
-#else
-    pthread_cond_destroy( &c->cond );
-#endif
-    tr_free( c );
-}
-
-
 /***
 ****  PATHS
 ***/

libtransmission/platform.h

@@ -25,7 +25,6 @@
 #define TR_PLATFORM_H
 
 typedef struct tr_lock   tr_lock;
-typedef struct tr_cond   tr_cond;
 typedef struct tr_thread tr_thread;
 
 const char * tr_getHomeDirectory( void );
@@ -42,12 +41,6 @@ void         tr_lockLock       ( tr_lock * );
 void         tr_lockUnlock     ( tr_lock * );
 int          tr_lockHave       ( const tr_lock * );
 
-tr_cond *    tr_condNew       ( void );
-void         tr_condFree      ( tr_cond * );
-void         tr_condSignal    ( tr_cond * );
-void         tr_condBroadcast ( tr_cond * );
-void         tr_condWait      ( tr_cond *, tr_lock * );
-
 struct in_addr; /* forward declaration to calm gcc down */
 int
 tr_getDefaultRoute( struct in_addr * addr );