lib/38948: libpthread, java: thread awakening itself

[ad%netbsd.org@localhost]

>Number:         38948
>Category:       lib
>Synopsis:       libpthread, java: thread awakening itself
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 12 15:25:00 +0000 2008
>Originator:     Andrew Doran
>Release:        4.99.64
>Organization:
The NetBSD Project
>Environment:
n/a
>Description:
This is a harmless bug, but should be fixed.

   230      2 java     _lwp_park(0xae3ff9e0, 0x2, 0xbb92bd14, 0xbb92bd14) 
Err#37 EALREADY

The thread is awakening itself: thread 2 is asking to unpark thread 2.
This may be a result of the sleep ending early, and the condvar code
issuing a pthread_cond_broadcast() on the condvar as a result.

>How-To-Repeat:
ktruss -p `pgrep java` while running apache tomcat.

>Fix:
When removing self from a condvar after an error from _lwp_park(), don't
issue a future unpark operation on self.