svn commit: r218970 - in head/sys: compat/linux sys

[Lucius Windschuh]

Hi John, hi Dmitry.

2011/2/23 John Baldwin <jhb at freebsd.org>:
> New Revision: 218970
> [...]
> Log:
>  Use umtx_key objects to uniquely identify futexes.  Private futexes in
>  different processes that happen to use the same user address in the
>  separate processes will now be treated as distinct futexes rather than the
>  same futex.  We can now honor shared futexes properly by mapping them to a
>  PROCESS_SHARED umtx_key.  Private futexes use THREAD_SHARED umtx_key
>  objects.

This change breaks linux-jdk-1.6.0, at least for me on FreeBSD 9 i386:

$ /usr/local/linux-sun-jdk1.6.0/bin/java
Usage: java [-options] class [args...]
           (to execute a class)
   or  java [-options] -jar jarfile [args...]
           (to execute a jar file)

where options include:
    -d32          use a 32-bit data model if available

    -d64          use a 64-bit data model if available
    -client       to select the "client" VM
    -server       to select the "server" VM
    -hotspot      is a synonym for the "client" VM  [deprecated]
                  The default VM is server,
                  because you are running on a server-class machine.

    -cp <class search path of directories and zip/jar files>
    -classpath <class search path of directories and zip/jar files>
                  A : separated list of directories, JAR archives,
                  and ZIP archives to search for class files.
    -D<name>=<value>
                  set a system property
    -verbose[:class|gc|jni]
                  enable verbose output
    -version      print product version and exit
    -version:<value>
                  require the specified version to run
    -showversion  print product version and continue
    -jre-restrict-search | -jre-no-restrict-search
                  include/exclude user private JREs in the version search
    -? -help      print this help message
    -X            print help on non-standard options
    -ea[:<packagename>...|:<classname>]
    -enableassertions[:<packagename>...|:<classname>]
                  enable assertions
    -da[:<packagename>...|:<classname>]
    -disableassertions[:<packagename>...|:<classname>]
                  disable assertions
    -esa | -enablesystemassertions
                  enable system assertions
    -dsa | -disablesystemassertions
                  disable system assertions
    -agentlib:<libname>[=<options>]
                  load native agent library <libname>, e.g. -agentlib:hprof
                    see also, -agentlib:jdwp=help and -agentlib:hprof=help
    -agentpath:<pathname>[=<options>]
                  load native agent library by full pathname
    -javaagent:<jarpath>[=<options>]
                  load Java programming language agent, see java.lang.instrument
    -splash:<imagepath>
                  show splash screen with specified image
^T
load: 1.62  cmd: java 4007 [futex] 3.33r 0.00u 0.00s 0% 10784k
(... wait a while)
^T
load: 1.62  cmd: java 4007 [futex] 4.45r 0.00u 0.00s 0% 10784k
(... doesn't finish)

With r218969, the process finishes as expected.

BTW, is there an easy way to debug such futex issues, other than
perhaps linux_kdump?

Lucius