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From: stephen@dcl-cs.UUCP (Stephen J. Muir)
Newsgroups: net.bugs.4bsd
Subject: Bug in flock(3) in 4.2BSD.
Message-ID: <863@dcl-cs.UUCP>
Date: Wed, 11-Dec-85 22:39:22 EST
Article-I.D.: dcl-cs.863
Posted: Wed Dec 11 22:39:22 1985
Date-Received: Mon, 16-Dec-85 04:18:43 EST
Reply-To: stephen@comp.lancs.ac.uk (Stephen J. Muir)
Organization: Department of Computing at Lancaster University.
Lines: 31

Consider the following scenario:
1. process 0 starts and opens a file
2. process 1 starts and opens the same file
3. process 2 starts and opens the same file
4. process 1 applies a shared lock and succeeds
5. process 2 attempts to apply an exclusive lock and hangs
6. process 1 attempts to upgrade its lock to an exclusive one and hangs

Process 1 should not have hung here.

7. I kill process 2

Process 1 is still hung.

8. I kill process 1
9. process 3 starts and opens the same file
10. process 3 attempts to apply an exclusive lock and hangs

Process 3 should not have hung here.

11. I kill processes 0 & 3
12. process 4 starts and opens the same file
13. process 4 applies an exclusive lock and succeeds

This is correct.
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