threads/119920: fork broken in libpthread

[Bernard Buri]

>Number:         119920
>Category:       threads
>Synopsis:       fork broken in libpthread
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    freebsd-threads
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Jan 23 10:30:02 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Bernard Buri
>Release:        6.3-RELEASE
>Organization:
ask!
>Environment:
FreeBSD host.domain 6.3-RELEASE FreeBSD 6.3-RELEASE #12: Mon Jan 21 13:23:06 CET 2008     root at host.domain:/usr/obj/usr/src/sys/SMP  i386
>Description:
Sometimes, when a multithreaded application tries to spawn another process, the child process loops with 100% CPU in the fork () procedure.

Here is the backtrace after attaching gdb to the child process:
#0  0x6809c198 in pthread_sigmask () from /lib/libpthread.so.2
#1  0x6809c148 in sigprocmask () from /lib/libpthread.so.2
#2  0x680a660c in pthread_mutexattr_init () from /lib/libpthread.so.2
#3  0x680992db in fork () from /lib/libpthread.so.2
#4  0x68ae735d in jdk_fork_wrapper ()
   from /usr/local/jdk1.6.0/jre/lib/i386/libjava.so
#5  0x68ae798c in Java_java_lang_UNIXProcess_forkAndExec ()
   from /usr/local/jdk1.6.0/jre/lib/i386/libjava.so
#6  0x68b1868e in ?? ()
#7  0x08a958ec in ?? ()
#8  0xbf1778a0 in ?? ()
..
>How-To-Repeat:
Most of the time, the problem was observed with a java process, but also, after logging into a gnome session, there are sometimes processes running 100% CPU.

I can regularly reproduce this behaviour with Eclipse CDT (C/C++ Development Tools).
>Fix:
The problem could not be observed with libthr.

>Release-Note:
>Audit-Trail:
>Unformatted: