sched: Disable the scheduling when send SIGCHLD signal

Disable the scheduling to prevent other tasks from being
deleted after they are awakened

Signed-off-by: zhangyuan29 <zhangyuan29@xiaomi.com>

sched/task/task_exithook.c

@@ -448,6 +448,12 @@ void nxtask_exithook(FAR struct tcb_s *tcb, int status)
   irqstate_t flags = enter_critical_section();
 #endif
 
+  /* Disable the scheduling function to prevent other tasks from
+   * being deleted after they are awakened
+   */
+
+  sched_lock();
+
   /* Send the SIGCHLD signal to the parent task group */
 
   nxtask_signalparent(tcb, status);
@@ -456,6 +462,8 @@ void nxtask_exithook(FAR struct tcb_s *tcb, int status)
 
   nxtask_exitwakeup(tcb, status);
 
+  sched_unlock();
+
   /* Leave the task group.  Perhaps discarding any un-reaped child
    * status (no zombies here!)
    */