commit e7b3e6817421763eee37cb35ef8627bdd37a3690
Author: Chunyu Hu <chuhu@redhat.com>
Date:   Wed May 6 18:59:43 2020 +0800

    Wait child with os.wait()
    
    os.popen() is an async method, it fork() child and exec() in child
    with the arg command. If it's slow enough, main process could get
    incomplete result.
    
    During our test, we find python3 is faster than python2,after coverting
    to python3, 'groupadd' usually doesn't finish when the followed step iter
    on groups, we would get '-1' as the groupid and lead to error.
    
    To reproduce it with python3:
    /root/rpmbuild/BUILD/libhugetlbfs-2.21/huge_page_setup_helper.py <<EOF
    128
    hugepages
    hugepages root
    EOF
    
    ...
    hugeadm:ERROR: Invalid group specification (-1)
    ...
    
    Signed-off-by: Chunyu Hu <chuhu@redhat.com>

diff --git a/huge_page_setup_helper.py b/huge_page_setup_helper.py
index a9ba2bf..01fc8dc 100755
--- a/huge_page_setup_helper.py
+++ b/huge_page_setup_helper.py
@@ -169,6 +169,10 @@ else:
         os.popen("/usr/sbin/groupadd %s" % userGroupReq)
     else:
         print("/usr/sbin/groupadd %s" % userGroupReq)
+
+    # wait for the groupadd finish
+    os.wait()
+
     groupNames = os.popen("/usr/bin/getent group %s" % userGroupReq).readlines()
     for line in groupNames:
         curGroupName = line.split(":")[0]
@@ -244,6 +248,9 @@ else:
     print("/usr/bin/hugeadm --set-recommended-shmmax")
     print()
 
+# wait for the hugepage setups finish
+os.wait()
+
 # figure out what that shmmax value we just set was
 hugeadmexplain = os.popen("/usr/bin/hugeadm --explain 2>/dev/null").readlines()
 for line in hugeadmexplain: