[GitHub] [incubator-nuttx] patacongo commented on a diff in pull request #6338: sched/semaphore: sem_wait should not report ECANCELED

[GitBox <gi...@apache.org>]

patacongo commented on code in PR #6338:
URL: https://github.com/apache/incubator-nuttx/pull/6338#discussion_r883710600


##########
sched/semaphore/sem_wait.c:
##########
@@ -251,37 +251,21 @@ int nxsem_wait_uninterruptible(FAR sem_t *sem)
 
 int sem_wait(FAR sem_t *sem)
 {
-  int errcode;
   int ret;
 
   /* sem_wait() is a cancellation point */
 
-  if (enter_cancellation_point())
-    {
-#ifdef CONFIG_CANCELLATION_POINTS
-      /* If there is a pending cancellation, then do not perform
-       * the wait.  Exit now with ECANCELED.
-       */
-
-      errcode = ECANCELED;
-      goto errout_with_cancelpt;
-#endif
-    }
+  enter_cancellation_point();

Review Comment:
   I think that this has an unacceptable side effect.  In the deferred cancellation mode, there could be a cancellation pending on entry into sem_wait().
   
   POSIX required that the deferred cancellation pend until a cancellation point function is called.  But with this change, sem_wait() will ignore the deferred cancelation and just continue to wait.
   
   The result would be that the cancellation is lost.



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