Re: Linux 2.4 VS 2.6 fork VS thread creation time test

[David Lang]

I just found part of a thread from early april about zombie problems in
both 2.4 and 2.6
thread titles are
Exploring sigqueue leak (was: Strange 'zombie' problem both in 2.4 and
2.6)
Local DoS (was: Strange 'zombie' problem both in 2.4 and 2.6)


one piece of info that those threads were looking for is the sigqueue info

on my box I get

baseline:/proc/sys/kernel# grep sigqueue /proc/slabinfo
sigqueue              22     24    160   24    1 : tunables  120   60    8
: slabdata      1      1      0
baseline:/proc/sys/kernel# cat /proc/sys/kernel/rtsig-*
2048
1

default rtsig-max was 1024, I bumped it up to 2048 but it did not affect
the problem

one interesting point is that rtsig-nr is normally 0 but when it is in the
error condition that causes all children to become zombies it sits at 1

since my last message didn't go out to linux-kernel and I didn't notice it
I am attaching the source for a program that also generates this problem

David Lang


On Sun, 23 May 2004, David Lang wrote:

> Date: Sun, 23 May 2004 17:46:40 -0700 (PDT)
> From: David Lang <dlang@xxxxxxxxxxxxxxxxxx>
> To: Alexander Nyberg <alexn@xxxxxxxxx>
> Subject: Re: Linux 2.4 VS 2.6 fork VS thread creation time test
>
> > >
> > > unfortunantly trying to leave strace attached while running the test slows
> > > it down to ~1200 forks/sec and the problem never forms.
> >
> > Could you please show me this program? I wrote a small one together
> > myself but I cannot reproduce this problem, maybe because of UP, don't
> > know.
>
> Ok, here is another program that has the same problem.
>
> David Lang
>
> --
> "Debugging is twice as hard as writing the code in the first place.
> Therefore, if you write the code as cleverly as possible, you are,
> by definition, not smart enough to debug it." - Brian W. Kernighan
>
>

-- 
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan

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