Date: Tue, 8 Sep 2009 18:22:03 +0800 From: Cheng Renquan <crquan@gmail.com> To: Ivan Radovanovic <rivanr@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Kernel panic caused by fork Message-ID: <91b13c310909080322s21e0fb02o423434206e5f96f6@mail.gmail.com> In-Reply-To: <4AA4E7A7.60503@gmail.com> References: <4AA4E7A7.60503@gmail.com>
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On Mon, Sep 7, 2009 at 6:59 PM, Ivan Radovanovic<rivanr@gmail.com> wrote:
> I was testing FreeBSD's behavior when running many threads at the same ti=
me
> (and I find it performs excellent) when I wanted to test how system will
> behave towards program that spawns itself too many times. I wrote a very
> simple program
>
> #include <sys/types.h>
> #include <unistd.h>
>
> int main() {
> =C2=A0while(1)
> =C2=A0 fork();
> =C2=A0return 0;
> }
>
> After running this program I got kernel panic with message
> "get_pv_entry: increase vm.pmap.shpgperproc"
> IMHO it is not very good idea to bring entire system down if one process
> misbehaves in this way, it is maybe much better to kill offending process
> and to send this message to system log. I am not sure whether the panic i=
s
> actually caused by process forking forever or when the system tries to
> create new process when maxproc limit is already reached (since system is
> only printing warning message that maxproc limit is reached and it only
> panics when I try to start new process (like ps)).
> System is FreeBSD 7.2-STABLE
It's just the "fork bomb" problem, all operating system kernels cannot
deal with it well,
http://en.wikipedia.org/wiki/Fork_bomb
And it's really a system administration problem rather than a kernel proble=
m,
--=20
Cheng Renquan (=E7=A8=8B=E4=BB=BB=E5=85=A8), from Shenzhen, China
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