Is it normal that a user can take down the whole system by using too much memory?

[John Howie]

Hi Brennan,

Do ‘man -k limit’ for details of means to restrict resource consumption. In particular, check out limits(1) and rctl(8).

Variations of this problem have been around forever. An oldie but goldie is:

main () { while (1) { fork (); } }

I cannot say why you are getting the results you see on your specific system. I would check limits to see where they are set, and tweak them.

Cheers,

John




Sent from my iPhone

> On Jun 2, 2018, at 15:20, Brennan Vincent <brennan at umanwizard.com> wrote:
> 
> The attached program `eatmem.c` is a simple example to waste N gigs of memory as quickly as possible.
> 
> When I run something like `eatmem 32` (on a system with less than 32GB of RAM), about half the time everything works fine: the system quickly runs out of RAM and swap, the kernel kills `eatmem`, and everything recovers. However, the other half of the time, the system becomes completely unusable: my ssh session is killed, important processes like `init` and `getty` are killed, and it's impossible to even log into the system (the local terminal is unresponsive, and I can't ssh in because sshd is killed immediately whenever it tries to run). The only way to recover is by rebooting.
> 
> Is this expected behavior?
> 
> My system details are as follows:
> FreeBSD 12 CURRENT x86_64 guest on VMWare Fusion.
> ram: 8 GB
> swap: 1 GB
> Host: macbook pro running macOS.
> <eatmem.c>
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