Re: Probably local denial of service

On Mon Apr 13, 2026 at 8:08 AM UTC, Lloyd wrote:
> Hi Henrich,
>
> The way I trigger it is different. With the sparse file created and
> in the current directory, I execute a grep - the bug seems to be
> triggered after initiating a ^C to the grep. CPU will climb to max,
> any open SSH sessions time out and the console is unresponsive to
> any input. I suppose I didn't wait long enough but the one time I
> was able to trigger ddb it noted a kernel: double fault trap so I
> assume the system is halted at that point. It required a poweroff
> of the VM to recover.
>
> Either way, a non-root user should not be able to do this!
>
> I forgot to mention: I was testing this on amd64 VMware ESXi.
>
> I'm curious what would happen on other architectures like SPARC.
>
> Regards
> Lloyd

Hi LLoyd,

I tested a couple of times with grep and had no crash. It does hang
though, and I agree that it makes it unresponsive.

bsd# time grep foobar 1
^C^C^C^C^C  838m18.24s real   160m44.71s user   552m45.29s system

(I waited quite a while before doing ctrl+c, and it took a very long
time to die.)

-Henrich