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Hi,

I wanted to test my RAM, so I installed memtester.

On my machine with 2*4GB RAM, I typed in:
$ memtester 8GB 10

Immediately, the computer got frozen...

According to the docs (man page):
"memtester  will malloc(3) the amount of memory specified, if possible.  If 
this fails, it will decrease the amount of memory requested until it succeeds"

So, apparently, memtester succeeded reserving 8GB. I would be glad to 
understand how, since:
1. My machine just has that amount physically, but with the OS+other running 
software, only 5794044 bytes are free
2. I have set up some paranoïd configurations so that no user process can 
request more than 2GB:
$  ulimit -m
2097152

How is it possible that memtester did not got rejected by the OS when asking 
for more memory than available?
How is it possible that memtester did not got rejected by the user process's 
limits?
How to prevent memtester (and any other software) to crash my system by simply 
greedily asking for memory?

** Affects: linux (Ubuntu)
     Importance: Undecided
     Assignee: Colin Ian King (colin-king)
         Status: New

-- 
memtester asks for memory, linux oom crashes computer
https://bugs.launchpad.net/bugs/1679740
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