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Date: Sat, 10 Feb 2001 11:31:40 +0900 (JST)
From: ohki@gssm.otsuka.tsukuba.ac.jp
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Subject: kern/24982: stack gap usage
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>Number:         24982
>Category:       kern
>Synopsis:       stack gap usage
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Feb 09 18:40:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Atsuo Ohki
>Release:        FreeBSD 4.2-RELEASE i386
>Organization:
GSSM, University of Tsukuba, Tokyo, Japan
>Environment:

	any system which have rfork() system call and RFMEM flag.

>Description:

	rfork() system call with RFMEM flag set causes
	two or more processes to share the same phisycal space.
	This means if those processes would require stack gap
	space at the same time, the contents of stack gap space would
	be messed up.  Processes under Liux-emulation encounter this
	problem (especially on dual CPU machines).

>How-To-Repeat:

	just try to run JDK1.3 demo programs on mixed mode java.
	demo programs drop into infinite loop at different point
	of each run.

>Fix:
	
	access to stack gap space must be controlled among
	processes which share the same phisycal space or
	stack gap space should not be shared.


>Release-Note:
>Audit-Trail:
>Unformatted:


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