The current memcg container seems to lead to lots of hangs/stalls.
Presumably the problem is with oom_score_adj and KASAN.
Executor process tree eats all memory and then the leaf process is killed
but the memory is not returned to memcg due to KASAN quarantine;
and the parent processes are protected from killing with oom_score_adj=-1000.
As the result the kernel locks up.
1. Don't use oom_score_adj=-1000. Instead bump leaf process score to 1000 (kill always).
2. Increase size of memcg to be larger than expected KASAN quarantine size.
adedaf77a1