[incubator-nuttx] 01/02: sched/sched/sched_waitid.c: Fix an error that occurs when a waiting task has already finished

[xi...@apache.org]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git

commit 1a9a71f47c2471cf48a7d059d3d447f5dd1c14cd
Author: Yoshinori Sugino <ys...@gmail.com>
AuthorDate: Fri Dec 4 15:12:06 2020 +0900

    sched/sched/sched_waitid.c: Fix an error that occurs when a waiting task has already finished
    
    Summary:
     - Fix an error that occurs when a waiting task has already finished.
    
    Impact:
     - waitid
    
    Testing:
    hifive1-revb:nsh (CONFIG_SCHED_HAVE_PARENT=y, CONFIG_SCHED_CHILD_STATUS=y, CONFIG_SIG_DEFAULT=y)
    on QEMU
    
    static int task_main(int argc, char *argv[])
    {
      return 0;
    }
    
    int main(int argc, FAR char *argv[])
    {
      siginfo_t info;
      int pid;
      int ret;
    
      pid = task_create("task", 224, 1024, task_main, NULL);
    
      sleep(1);
    
      ret = waitid(P_PID, pid, &info, WEXITED);
    
      assert(ret == 0);
    
      return 0;
    }
---
 sched/sched/sched_waitid.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/sched/sched/sched_waitid.c b/sched/sched/sched_waitid.c
index 2001934..8aac112 100644
--- a/sched/sched/sched_waitid.c
+++ b/sched/sched/sched_waitid.c
@@ -178,15 +178,17 @@ int nx_waitid(int idtype, id_t id, FAR siginfo_t *info, int options)
        */
 
       ctcb = nxsched_get_tcb((pid_t)id);
-
+      if (ctcb != NULL)
+        {
 #ifdef HAVE_GROUP_MEMBERS
-      if (ctcb == NULL || ctcb->group->tg_pgrpid != rtcb->group->tg_grpid)
+          if (ctcb->group->tg_pgrpid != rtcb->group->tg_grpid)
 #else
-      if (ctcb == NULL || ctcb->group->tg_ppid != rtcb->pid)
+          if (ctcb->group->tg_ppid != rtcb->pid)
 #endif
-        {
-          ret = -ECHILD;
-          goto errout;
+            {
+              ret = -ECHILD;
+              goto errout;
+            }
         }
 
       /* Does this task retain child status? */