[Bug 1294200] [NEW] test linked against nih-dbus-tool-generated libraryis not thread-safe

[Serge Hallyn]

Public bug reported:

I've taken the libnih source for trusty, and added '--enable-threads' to
the three dh_auto_configure lines in debian/rules, rebuilt ,and
installed the result.  Then I took the source for cgmanager package,
rebuilt, and installed.

Finally I took github.com/cgmanager/cgmanager, copied the configure.ac,
Makefile.am, and tests/cgm-concurrent.c into the cgmanager package
source, and built tests/cgm-concurrent.c.

The cgm-concurrent.c only connects to the cgmanager dbus server, sends a
ping method, and disconnects - with one connection per thread.

When I do cgm-concurrent -i 100 -j 30 -c (meaning use 30 threads and do
100 full iterations, and don't do any extra dbus calls), I get pretty
random dumps.  Here is one example:

(gdb) where
#0  0x00007ffff71c5f79 in __GI_raise (sig=sig at entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x00007ffff71c9388 in __GI_abort () at abort.c:89
#2  0x00007ffff71bee36 in __assert_fail_base (fmt=0x7ffff73104b8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion at entry=0x7ffff756793c "mutex->__data.__owner == 0", 
    file=file at entry=0x7ffff7567908 "../nptl/pthread_mutex_lock.c", line=line at entry=116, function=function at entry=0x7ffff7567a40 <__PRETTY_FUNCTION__.8500> "__pthread_mutex_lock") at assert.c:92
#3  0x00007ffff71beee2 in __GI___assert_fail (assertion=0x7ffff756793c "mutex->__data.__owner == 0", file=0x7ffff7567908 "../nptl/pthread_mutex_lock.c", line=116, 
    function=0x7ffff7567a40 <__PRETTY_FUNCTION__.8500> "__pthread_mutex_lock") at assert.c:101
#4  0x00007ffff755f52f in __GI___pthread_mutex_lock (mutex=0xfefefefefefefe00) at ../nptl/pthread_mutex_lock.c:116
#5  0x00007ffff779fa45 in _dbus_platform_rmutex_lock (mutex=<optimized out>) at ../../dbus/dbus-sysdeps-pthread.c:156
#6  0x00007ffff77943f5 in _dbus_rmutex_lock (mutex=<optimized out>) at ../../dbus/dbus-threads.c:176
#7  0x00007ffff7782b40 in dbus_connection_get_data (connection=0x7fffc0040e70, slot=0) at ../../dbus/dbus-connection.c:5979
#8  0x00007ffff79bb766 in nih_dbus_setup () from /lib/x86_64-linux-gnu/libnih-dbus.so.1
#9  0x0000000000401cbe in cgm_dbus_connect ()
#10 0x0000000000401e5d in do_function ()
#11 0x0000000000401ec4 in concurrent ()
#12 0x00007ffff755d182 in start_thread (arg=0x7fffd8ff9700) at pthread_create.c:312
#13 0x00007ffff728a12d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Sometimes they show up in nih_free, where usually the thing being freed
has a ->next which points to a member function;  sometimes they show up
in the dbus library at various points.

I may well be doing something wrong, but I don't know what.  If we can't
either fix what I'm doing wrong or fix libnih or libdbus (if those are
being buggy), then I guess I'll have to mutex the connection among all
threads.

** Affects: cgmanager (Ubuntu)
     Importance: Critical
         Status: New

** Affects: dbus (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: libnih (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: lxc (Ubuntu)
     Importance: Critical
         Status: New

** Also affects: dbus (Ubuntu)
   Importance: Undecided
       Status: New

** Also affects: cgmanager (Ubuntu)
   Importance: Undecided
       Status: New

** Also affects: lxc (Ubuntu)
   Importance: Undecided
       Status: New

** Changed in: lxc (Ubuntu)
   Importance: Undecided => Critical

** Changed in: cgmanager (Ubuntu)
   Importance: Undecided => Critical

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https://bugs.launchpad.net/bugs/1294200

Title:
  test linked against nih-dbus-tool-generated libraryis not thread-safe

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