Fix concurrent bitmap update in GC_dirty

Issue #235 (bdwgc).

* darwin_stop_world.c [!GC_NO_THREADS_DISCOVERY]
(GC_suspend_thread_list): Call GC_acquire_dirty_lock and
GC_release_dirty_lock around thread_suspend().
* darwin_stop_world.c (GC_stop_world): Likewise.
* include/private/gc_priv.h (set_pht_entry_from_index_safe): Remove
unused macro.
* include/private/gc_priv.h [THREADS] (GC_acquire_dirty_lock,
GC_release_dirty_lock): Define new macro; move comment from
win32_threads.c.
* include/private/gc_priv.h [THREADS && !GC_DISABLE_INCREMENTAL]
(GC_fault_handler_lock): Declare global variable (even if not
MPROTECT_VDB).
* os_dep.c [!GC_DISABLE_INCREMENTAL] (async_set_pht_entry_from_index):
Define even if not MPROTECT_VDB; reformat comments.
* os_dep.c [!GC_DISABLE_INCREMENTAL && AO_HAVE_test_and_set_acquire]
(GC_fault_handler_lock): Likewise.
* os_dep.c [THREADS && AO_HAVE_test_and_set_acquire]
(async_set_pht_entry_from_index): Use GC_acquire_dirty_lock and
GC_release_dirty_lock; remove wrong comment.
* os_dep.c [THREADS && !AO_HAVE_test_and_set_acquire]
(currently_updating, async_set_pht_entry_from_index): Remove incorrect
implementation.
* os_dep.c [!GC_DISABLE_INCREMENTAL] (GC_dirty_inner): Call
async_set_pht_entry_from_index instead of set_pht_entry_from_index;
remove FIXME.
* pthread_stop_world.c [GC_ENABLE_SUSPEND_THREAD] (GC_suspend_thread):
Refine comment for AO_store_release call; call GC_acquire_dirty_lock
and GC_release_dirty_lock around a block of RAISE_SIGNAL() and
sem_wait().
* pthread_stop_world.c [GC_OPENBSD_UTHREADS] (GC_suspend_all): Call
GC_acquire_dirty_lock and GC_release_dirty_lock around
pthread_suspend_np().
* pthread_stop_world.c [!GC_OPENBSD_UTHREADS] (GC_suspend_all): Add
comment.
* pthread_stop_world.c [!GC_OPENBSD_UTHREADS && !NACL] (GC_stop_world):
If GC_manual_vdb then call GC_acquire_dirty_lock and
GC_release_dirty_lock around a block of GC_suspend_all() and
suspend_restart_barrier(); add comment.
* win32_threads.c (GC_suspend): Use GC_acquire_dirty_lock and
GC_release_dirty_lock (regardless of MPROTECT_VDB).

1 files changed, 2 insertions, 12 deletions

diff --git a/win32_threads.c b/win32_threads.c
index 2701b11c..225d8e0d 100644
--- a/win32_threads.c
+++ b/win32_threads.c
@@ -1186,15 +1186,7 @@ STATIC void GC_suspend(GC_thread t)
       return;
     }
 # endif
-# if defined(MPROTECT_VDB)
-    /* Acquire the spin lock we use to update dirty bits.       */
-    /* Threads shouldn't get stopped holding it.  But we may    */
-    /* acquire and release it in the UNPROTECT_THREAD call.     */
-    while (AO_test_and_set_acquire(&GC_fault_handler_lock) == AO_TS_SET) {
-      /* empty */
-    }
-# endif
-
+  GC_acquire_dirty_lock();
 # ifdef MSWINCE
     /* SuspendThread() will fail if thread is running kernel code.      */
     while (SuspendThread(THREAD_HANDLE(t)) == (DWORD)-1)
@@ -1204,9 +1196,7 @@ STATIC void GC_suspend(GC_thread t)
       ABORT("SuspendThread failed");
 # endif /* !MSWINCE */
   t -> suspended = (unsigned char)TRUE;
-# if defined(MPROTECT_VDB)
-    AO_CLEAR(&GC_fault_handler_lock);
-# endif
+  GC_release_dirty_lock();
   if (GC_on_thread_event)
     GC_on_thread_event(GC_EVENT_THREAD_SUSPENDED, THREAD_HANDLE(t));
 }