[ros-users] rosconsole initialization problem when linked with xenomai

[Mrinal Kalakrishnan]

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 at 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
>