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Date:      Thu, 2 May 1996 04:38:07 -0700 (PDT)
From:      Peter Wemm <peter>
To:        CVS-committers, cvs-all, cvs-sys
Subject:   cvs commit:  src/sys/kern kern_fork.c
Message-ID:  <199605021138.EAA18666@freefall.freebsd.org>

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peter       96/05/02 04:38:06

  Modified:    sys/kern  kern_fork.c
  Log:
  Fix a nasty bug that causes random crashes and lockups particularly on
  very busy servers (eg: news, web).  This is an interaction between
  embryonic processes that have not yet finished forking, and happen to
  cause the kernel VM space to grow, hitting the uninitialised variable.
  
  It was possible for this to strike at any time, depending on the size of
  your kernel and load patterns.  One machine had paniced occasionally
  when cron launches a job since before the 2.1 release.
  
  If you had "options DIAGNOSTIC", you may have seen references to bogus
  addresses like 0xdeadc142 and the like.
  
  This is a minimal change to fix the problem, it will probably be done
  better by reordering p_vmspace to be in the startzero section, but it
  becomes harder to validate then.
  
  It's been vulnerable since pmap.c rev 1.40 (Jan 9, 1995), so it's been a
  cause of problems since well before 2.0.5.  This was when the merged
  VM/buffer cache and the dynamic growing kernel VM space were first
  committed.  This probably fixes a few of PR's.
  
  Revision  Changes    Path
  1.21      +6 -1      src/sys/kern/kern_fork.c



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