memcg_max_usage_in_bytes from controllers in LTP failed with memory.memsw.max_usage_in_bytes

Issue found on 5.10.0-1035.36-oem with node spitfire

With patch for bug 1829979 applied locally via ACT, I can see this failure on this kernel:

 startup='Thu Jul 1 15:49:33 2021'
 memcg_max_usage_in_bytes_test 1 TINFO: timeout per run is 0h 5m 0s
 memcg_max_usage_in_bytes_test 1 TINFO: set /dev/memcg/memory.use_hierarchy to 0 failed
 memcg_max_usage_in_bytes_test 1 TINFO: Test memory.max_usage_in_bytes
 memcg_max_usage_in_bytes_test 1 TINFO: Running memcg_process --mmap-anon -s 4194304
 memcg_max_usage_in_bytes_test 1 TINFO: Warming up pid: 299052
 memcg_max_usage_in_bytes_test 1 TINFO: Process is still here after warm up: 299052
 memcg_max_usage_in_bytes_test 1 TPASS: memory.max_usage_in_bytes is 4194304-4325376 as expected
 memcg_max_usage_in_bytes_test 2 TINFO: Test memory.memsw.max_usage_in_bytes
 memcg_max_usage_in_bytes_test 2 TINFO: Running memcg_process --mmap-anon -s 4194304
 memcg_max_usage_in_bytes_test 2 TINFO: Warming up pid: 299068
 memcg_max_usage_in_bytes_test 2 TINFO: Process is still here after warm up: 299068
 memcg_max_usage_in_bytes_test 2 TPASS: memory.memsw.max_usage_in_bytes is 4194304-4325376 as expected
 memcg_max_usage_in_bytes_test 3 TINFO: Test reset memory.max_usage_in_bytes
 memcg_max_usage_in_bytes_test 3 TINFO: Running memcg_process --mmap-anon -s 4194304
 memcg_max_usage_in_bytes_test 3 TINFO: Warming up pid: 299084
 memcg_max_usage_in_bytes_test 3 TINFO: Process is still here after warm up: 299084
 memcg_max_usage_in_bytes_test 3 TPASS: memory.max_usage_in_bytes is 4194304-4325376 as expected
 memcg_max_usage_in_bytes_test 3 TPASS: memory.max_usage_in_bytes is 0-131072 as expected
 memcg_max_usage_in_bytes_test 4 TINFO: Test reset memory.memsw.max_usage_in_bytes
 memcg_max_usage_in_bytes_test 4 TINFO: Running memcg_process --mmap-anon -s 4194304
 memcg_max_usage_in_bytes_test 4 TINFO: Warming up pid: 299101
 memcg_max_usage_in_bytes_test 4 TINFO: Process is still here after warm up: 299101
 memcg_max_usage_in_bytes_test 4 TFAIL: memory.memsw.max_usage_in_bytes is 4333568, 4194304-4325376 expected
 memcg_max_usage_in_bytes_test 4 TPASS: memory.memsw.max_usage_in_bytes is 0-131072 as expected
 memcg_max_usage_in_bytes_test 5 TINFO: AppArmor enabled, this may affect test results
 memcg_max_usage_in_bytes_test 5 TINFO: it can be disabled with TST_DISABLE_APPARMOR=1 (requires super/root)
 memcg_max_usage_in_bytes_test 5 TINFO: loaded AppArmor profiles: none

 Summary:
 passed 5
 failed 1
 broken 0
 skipped 0
 warnings 0
 tag=memcg_max_usage_in_bytes stime=1625154573 dur=4 exit=exited stat=1 core=no cu=13 cs=15