kern/97591: 6.1-RELEASE crashes on fork bomb

[Matthieu Michaud]

The following reply was made to PR kern/97591; it has been noted by GNATS.

From: Matthieu Michaud <ohmer at epita.info>
To: Maxim Konovalov <maxim at macomnet.ru>
Cc: bug-followup at freebsd.org
Subject: Re: kern/97591: 6.1-RELEASE crashes on fork bomb
Date: Tue, 13 Jun 2006 02:16:32 +0200

 On Fri, 2006-06-09 at 21:40 +0400, Maxim Konovalov wrote: 
 > Hi Matthieu,
 > 
 > > >Description:
 > > my fresh installed 6.1-RELEASE workstation doesn't survive to a
 > > simple fork bomb. after launching the bomb, it freezes a few seconds
 > > and then my computer reboots. afair, 5.4 systems survived it.
 > >
 > > i didn't tweak my kernel, i just use home compiled GENERIC without
 > > overriden CFLAGS. everything is almost default install. what about
 > > adding a forkbomb in regression tests ?
 > 
 > Please clarify what you mean by "home compiled GENERIC"?  Do you
 > change anything there?  Have you changed anything in /boot/loader.conf
 > or /etc/sysctl.conf?
 
 i meant that i used the official GENERIC kernel configuration file but i
 compiled it myself. the only kernel module i use is snd_ich (and sound
 obviously). that's stick into my /boot/loader.conf and i didn't set any
 value with /etc/sysctl.conf
 
 > > >How-To-Repeat:
 > > echo 'int main() { for(;;) fork(); }' | gcc -x c - && ./a.out
 > 
 > While we definitly have some problems in pmap(9) code in 7.0 aka HEAD
 > I can't reproduce the problem on RELENG_6 system.
 
 i tried to reproduce it but couldn't. when i tried it, just
 before filling a PR, it did exactly the same thing 3 times : run, fork
 few seconds and suddenly reboot. i can't explain it. 
 
 > Please try to obtain a backtrace from the kernel core file or ddb.
 > 
 > http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug.html
 
 i activated it, i'll try to crash it again, have a core dump and send
 useful information. for now, i don't see any reason to keep this PR
 open as it seem to be a very rare case.
 
 -- 
 Matthieu Michaud