Fix change to prevent cancel signal in unsafe places.

The bits tested to decide when to delay the return when switching
off async cancel mode were wrong.  Fix that.  Also close a race
condition in pthread_cancel where the bit indicating the cancellation
is unconditionally set even if the cancel type might have changed.

1 files changed, 2 insertions, 6 deletions

diff --git a/nptl/cancellation.c b/nptl/cancellation.c
index 4d528cf..2a6f83d 100644
--- a/nptl/cancellation.c
+++ b/nptl/cancellation.c
@@ -72,10 +72,6 @@ __pthread_disable_asynccancel (int oldtype)
   struct pthread *self = THREAD_SELF;
   int newval;
 
-#ifdef THREAD_ATOMIC_AND
-  THREAD_ATOMIC_AND (self, cancelhandling, ~CANCELTYPE_BITMASK);
-  newval = THREAD_GETMEM (self, cancelhandling);
-#else
   int oldval = THREAD_GETMEM (self, cancelhandling);
 
   while (1)
@@ -93,13 +89,13 @@ __pthread_disable_asynccancel (int oldtype)
       /* Prepare the next round.  */
       oldval = curval;
     }
-#endif
 
   /* We cannot return when we are being canceled.  Upon return the
      thread might be things which would have to be undone.  The
      following loop should loop until the cancellation signal is
      delivered.  */
-  while (__builtin_expect (newval & CANCELED_BITMASK, 0))
+  while (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
+			   == CANCELING_BITMASK, 0))
     {
       lll_futex_wait (&self->cancelhandling, newval, LLL_PRIVATE);
       newval = THREAD_GETMEM (self, cancelhandling);