Subject: kern/7478: kernel panic
To: None <>
From: Charlie Root <>
List: netbsd-bugs
Date: 04/26/1999 11:21:12
>Number:         7478
>Category:       kern
>Synopsis:       kernel panic
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 26 11:20:01 1999
>Originator:     Manfred Petz
	SIS Datenverarbeitung GmbH, Vienna
>Release:        NetBSD 1.4_ALPHA
System: NetBSD bsd 1.4_BETA NetBSD 1.4_BETA (POROS) #0: Mon Apr 26 16:49:21 CEST 1999 root@bsd:/usr/src/sys/arch/i386/compile/POROS i386


	System can be crashed with a fork bomb. 


	How I did:

		while (1) {
			sleep (1);
			fork ();

	The sleep() appears to be important, but maybe that's just a 

	- I started top(1) on a VC.
	- Telnet into the box and started the fork bomb from the telnet session.
	- After a few seconds the system couldn't fork anymore. I pressed
	  ^C. All processes disappeared.
	- Then I started the fork bomb again, waited again until no more
	  processes could be started.
	- Pressed ^C -> panic in the same moment. 

	I repeated that several times. Always the same situation.

        kernel: page fault trap, code=0 
	Stopped at _gdt_compact+0x40            movl 0x68(%ecx),%esi

	Sorry - no dump since this should be nicely reproducible and the 
	system panics again inside ddb when trying to dump. :-)

	If you cannot reproduce then please drop me an email so I can tell you 
	more. My config is available at

	But I don't think this has to do with a particular configuration.