threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B

[Attilio Rao]

The following reply was made to PR threads/136345; it has been noted by GNATS.

From: Attilio Rao <attilio at freebsd.org>
To: Rink Springer <rink at freebsd.org>
Cc: FreeBSD-gnats-submit at freebsd.org, freebsd-threads at freebsd.org
Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock 
	with write lock in thread B
Date: Sun, 5 Jul 2009 16:48:27 +0200

 2009/7/5 Rink Springer <rink at freebsd.org>:
 > Did some more testing; it works fine on Solaris 9 and 10. Also, the
 > deadlock doesn't appear on FreeBSD 6.1-STABLE (Sep 2006). Perhaps this
 > is a libthr issue?
 
 I think that rdlock_count in libthr is not updated properly.
 Can you test the following patch:
 http://www.freebsd.org/~attilio/libthr.diff
 
 Thanks,
 Attilio
 
 
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