Hey Josh,

Thanks for the clarification, looks like I need to dig into this a little more.

- Mrinal

On Tue, Nov 9, 2010 at 7:07 PM, Josh Faust <jfaust@willowgarage.com> wrote:
> This is only a problem across different compilation units.  Within the same
> compilation unit construction order is defined as the order they're defined
> in that unit.
> Josh
>
> On Tue, Nov 9, 2010 at 6:47 PM, Mrinal Kalakrishnan <mail@mrinal.net> wrote:
>>
>> I think that my problem could indeed be a rosconsole bug.
>>
>> There are two global variables in rosconsole.cpp (among others):
>>
>>    boost::mutex g_init_mutex;
>>
>> and
>>
>>    StaticInit g_static_init;
>>
>> Unfortunately the constructor of g_static_init depends on g_init_mutex
>> being initialized, because it attempts to lock the mutex. But I
>> believe the order of construction of global variables can never be
>> guaranteed, so the mutex could get locked before it is initialized.
>>
>> I'm not able to think of a thread-safe way to get around this yet.
>> I'll ticket this if someone can confirm that it's a bug.
>>
>> - Mrinal
>>
>> On Tue, Nov 9, 2010 at 3:43 PM, Mrinal Kalakrishnan <mail@mrinal.net>
>> wrote:
>> > Hello,
>> >
>> > I have a strange problem when linking a ROS application with Xenomai.
>> > It appears that the constructor for some global objects of rosconsole
>> > is waiting on a mutex (g_init_mutex). Here is the gdb backtrace when I
>> > kill the hanging program:
>> >
>> > #0  __lll_lock_wait ()
>> >    at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:136
>> > #1  0x00007ffff49de295 in _L_lock_949 () from /lib/libpthread.so.0
>> > #2  0x00007ffff49de0b8 in __pthread_mutex_lock (mutex=0x7ffff6304580)
>> >    at pthread_mutex_lock.c:61
>> > #3  0x00007ffff60f384a in boost::mutex::lock ()
>> >    at /usr/include/boost/thread/pthread/mutex.hpp:50
>> > #4  boost::unique_lock<boost::mutex>::lock ()
>> >    at /usr/include/boost/thread/locks.hpp:338
>> > #5  unique_lock () at /usr/include/boost/thread/locks.hpp:224
>> > #6  ros::console::initialize ()
>> >    at
>> > /tmp/buildd/ros-cturtle-ros-1.2.4/debian/ros-cturtle-ros/opt/ros/cturtle/ros/core/rosconsole/src/rosconsole/rosconsole.cpp:426
>> > #7  0x00007ffff60fc8d6 in __do_global_ctors_aux ()
>> >   from /opt/ros/cturtle/ros/core/rosconsole/lib/librosconsole.so
>> > #8  0x00007ffff60ef803 in _init ()
>> >   from /opt/ros/cturtle/ros/core/rosconsole/lib/librosconsole.so
>> > #9  0x00007fffffffe2d8 in ?? ()
>> > #10 0x00007ffff7ded6e9 in call_init (l=0x7ffff7fda510, argc=-164616432,
>> >    argv=0x7fffffffe2c8, env=0x7fffffffe2d8) at dl-init.c:70
>> > #11 0x00007ffff7ded86f in _dl_init (main_map=0x7ffff7ffb000, argc=1,
>> >    argv=0x7fffffffe2c8, env=0x7fffffffe2d8) at dl-init.c:134
>> > #12 0x00007ffff7ddfb2a in _dl_start_user () from
>> > /lib64/ld-linux-x86-64.so.2
>> > #13 0x0000000000000001 in ?? ()
>> > #14 0x00007fffffffe524 in ?? ()
>> > #15 0x0000000000000000 in ?? ()
>> >
>> > The same program works fine when not linked with xenomai. This is
>> > probably not a ROS bug, so I'm not creating a ticket, but I was
>> > wondering if anyone has seen this before, or has any other ideas. This
>> > problem either occurs or doesn't based on which objects I link into my
>> > final binary.
>> >
>> > - Mrinal
>> >
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