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Date: Wed, 23 Oct 1996 12:54:43 -0700 (PDT)
From: "Marc G. Fournier" <scrappy>
Message-Id: <199610231954.MAA06056@freefall.freebsd.org>
To: jdrobina@infinet.com, scrappy, freebsd-bugs
Subject: Re: kern/1599
Sender: owner-bugs@FreeBSD.ORG
X-Loop: FreeBSD.org
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Synopsis: panic: locking against myself

State-Changed-From-To: feedback-closed
State-Changed-By: scrappy
State-Changed-When: Wed Oct 23 12:53:42 PDT 1996
State-Changed-Why: 

Problem Still Exists:

The problen still exists, but I have discovered more information.  If you
login as root the problen does not occur.  But, if you login in as yourself,
the su to root the problem occurs.

I think I missed this fact before because I may have has mount_cd9660 sutuid
to root.

This sequence demonstrates the problem.

    1.  login with a non-root id
    2.  su
    3.  mount /cdrom        (The CD is the FreeBSD 2.1R live file system.)
    4.  cd /cdrom/usr/include
    5.  fgrep xx *.h

        panic: locking against myself

This also shows the problem.

    1.  login with a non-root id
    2.  su
    3.  mount /cdrom
    4.  exit
    5.  cd /cdrom/usr/include
    6.  fgrep xx *.h

However, if you login as root no error occurs.

    1.  login as root
    2.  mount /cdrom
    3.  cd /cdrom/usr/include
    4.  fgrep xx *.h

        works

A more stressful test works as well.

    1.  login as root
    2.  mount /cdrom
    3.  cd /cdrom/usr/include
    4.  for i in * ; do
        fgrep xx *.h */*.h
        done