From: Ivan Maidanski <ivmai@mail.ru>
Date: Tue, 21 Jun 2016 09:12:56 +0000 (+0300)
Subject: Fix GC_suspend_thread regarding potential cancellation of sem_wait
X-Git-Tag: gc7_6_0~28
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a98c23626538ce101d8903fdc5079c0a4efc2f7e;p=gc

Fix GC_suspend_thread regarding potential cancellation of sem_wait

* pthread_stop_world.c [GC_ENABLE_SUSPEND_THREAD] (GC_suspend_thread):
Call DISABLE_CANCEL before sem_wait, call RESTORE_CANCEL after it.
---

diff --git a/pthread_stop_world.c b/pthread_stop_world.c
index 1ee9ee8f..dad1fdc9 100644
--- a/pthread_stop_world.c
+++ b/pthread_stop_world.c
@@ -412,6 +412,7 @@ STATIC void GC_restart_handler(int sig)
 
     GC_API void GC_CALL GC_suspend_thread(GC_SUSPEND_THREAD_ID thread) {
       GC_thread t;
+      IF_CANCEL(int cancel_state;)
       DCL_LOCK_STATE;
 
       LOCK();
@@ -447,10 +448,13 @@ STATIC void GC_restart_handler(int sig)
       /* Wait for the thread to complete threads table lookup and   */
       /* stack_ptr assignment.                                      */
       GC_ASSERT(GC_thr_initialized);
+      DISABLE_CANCEL(cancel_state);
+                /* GC_suspend_thread is not a cancellation point.   */
       while (sem_wait(&GC_suspend_ack_sem) != 0) {
         if (errno != EINTR)
           ABORT("sem_wait for handler failed (suspend_self)");
       }
+      RESTORE_CANCEL(cancel_state);
       UNLOCK();
     }