One PG process eating more than 40GB of RAM and getting killed by OOM

Hello,

On my dev laptop, I have ~40GB free RAM. When launching a heavy
calculation in PostgreSQL (within a stored procedure), it consumes as
much memory as is available and then gets killed by OOM. There is only
one connected session.

I have the following settings, which look reasonable (to me):

shared_buffers = 512MB                  # min 128kB
#huge_pages = try                       # on, off, or try
temp_buffers = 512MB                    # min 800kB
#max_prepared_transactions = 0          # zero disables the feature
work_mem = 1GB                          # min 64kB
#hash_mem_multiplier = 1.0              # 1-1000.0 multiplier on hash
table work_mem
maintenance_work_mem = 1GB              # min 1MB
#autovacuum_work_mem = -1               # min 1MB, or -1 to use
maintenance_work_mem
#logical_decoding_work_mem = 64MB       # min 64kB
#max_stack_depth = 2MB                  # min 100kB
#shared_memory_type = mmap              # the default is the first option
dynamic_shared_memory_type = posix      # the default is the first option
#temp_file_limit = -1                   # limits per-process temp file space

This is PostgreSQL 14.7 running on Ubuntu 23.04

What can I do to prevent the crash?

Thanks for your help,