<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:p="urn:schemas-microsoft-com:office:powerpoint" xmlns:a="urn:schemas-microsoft-com:office:access" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" xmlns:b="urn:schemas-microsoft-com:office:publisher" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:c="urn:schemas-microsoft-com:office:component:spreadsheet" xmlns:odc="urn:schemas-microsoft-com:office:odc" xmlns:oa="urn:schemas-microsoft-com:office:activation" xmlns:html="http://www.w3.org/TR/REC-html40" xmlns:q="http://schemas.xmlsoap.org/soap/envelope/" xmlns:rtc="http://microsoft.com/officenet/conferencing" xmlns:D="DAV:" xmlns:Repl="http://schemas.microsoft.com/repl/" xmlns:mt="http://schemas.microsoft.com/sharepoint/soap/meetings/" xmlns:x2="http://schemas.microsoft.com/office/excel/2003/xml" xmlns:ppda="http://www.passport.com/NameSpace.xsd" xmlns:ois="http://schemas.microsoft.com/sharepoint/soap/ois/" xmlns:dir="http://schemas.microsoft.com/sharepoint/soap/directory/" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:dsp="http://schemas.microsoft.com/sharepoint/dsp" xmlns:udc="http://schemas.microsoft.com/data/udc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:sub="http://schemas.microsoft.com/sharepoint/soap/2002/1/alerts/" xmlns:ec="http://www.w3.org/2001/04/xmlenc#" xmlns:sp="http://schemas.microsoft.com/sharepoint/" xmlns:sps="http://schemas.microsoft.com/sharepoint/soap/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:udcs="http://schemas.microsoft.com/data/udc/soap" xmlns:udcxf="http://schemas.microsoft.com/data/udc/xmlfile" xmlns:udcp2p="http://schemas.microsoft.com/data/udc/parttopart" xmlns:st="" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv=Content-Type content="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 11 (filtered medium)"> <style>  </style> </head> <body lang=EN-US link=blue vlink=purple> <div class=Section1> Hello,<o:p></o:p> I am trying to investigate a crash in the dbus/dbus-glib code when trying to use dbus-glib to communicate with upstart 0.5.<o:p></o:p> <o:p> </o:p> Whenever a crash occurs, it always seems to be failing with a similar stack trace (see below).<o:p></o:p> The system is a 4 core cavium board (mips).<o:p></o:p> The test application is using 4 gthreads to make upstart async api calls to get upstart version in a while loop.<o:p></o:p> We have started a separate gthread to that does a g_main_loop_run() to handle responses from the async calls.<o:p></o:p> The application crashes after several successful api requests (1000 +)<o:p></o:p> The same code does not crash on a 2 core ppc based board.<o:p></o:p> <o:p> </o:p> The software versions we are using are as follows.<o:p></o:p> Upstart     Version   0.5<o:p></o:p> dbus-glib   Version  0.76<o:p></o:p> dbus         Version  1.2.1<o:p></o:p> glib           Version  2.6.6<o:p></o:p> <o:p> </o:p> The code flow looks like this<o:p></o:p> main()<o:p></o:p> {<o:p></o:p> g_type_init ();<o:p></o:p> g_thread_init(NULL);<o:p></o:p> dbus_g_thread_init();<o:p></o:p> //Create dbus connection<o:p></o:p> connection = dbus_g_bus_get (DBUS_BUS_SYSTEM,&error);<o:p></o:p> //Create upstart proxy to be shared by the 4 threads.<o:p></o:p> upstartProxy = dbus_g_proxy_new_for_name (connection,<o:p></o:p>                                                 UPSTART_SERVICE, /* "com.ubuntu.Upstart"*/<o:p></o:p>                                                 UPSTART_SERVICE_PATH, /* "/com/ubuntu/Upstart"*/<o:p></o:p>                                                 UPSTART_INTERFACE); /* "com.ubuntu.Upstart"*/<o:p></o:p> //Create mutex to lock/unlock before each of the threads makes the async call.<o:p></o:p> myMutex=g_mutex_new();<o:p></o:p> //Upstart Proxy and mutex are passed to all 4 threads.<o:p></o:p> //Create 1 gthread that runs g_main_loop_run() to handle callbacks for async calls.<o:p></o:p> //Create 4 gthreads to make async calls.<o:p></o:p> //call g_thread_join() on all 5 threads.<o:p></o:p> }<o:p></o:p> The code that starts the loopback thread looks like this<o:p></o:p> void ThreadMainLoop(void *ptr)<o:p></o:p> {<o:p></o:p>             GMainLoop *mainloop;<o:p></o:p>             mainloop = g_main_loop_new (NULL, FALSE);<o:p></o:p>             g_printf("\nStarting Signal and Async Callback Handler Thread");<o:p></o:p>             g_main_loop_run (mainloop);<o:p></o:p> }<o:p></o:p> <o:p> </o:p> The stack trace looks like this.<o:p></o:p> Core was generated by `sysmgr_test -ulg 4 -s 1'.<o:p></o:p> Program terminated with signal 11, Segmentation fault.<o:p></o:p> #0  0x2d485d94 in _dbus_connection_lock (connection=0x0)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/dbus/dbus/dbus-connection.c:355<o:p></o:p> 355       CONNECTION_LOCK (connection);<o:p></o:p> (gdb) bt<o:p></o:p> #0  0x2d485d94 in _dbus_connection_lock (connection=0x0)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/dbus/dbus/dbus-connection.c:355<o:p></o:p> #1  0x2d49f954 in _dbus_pending_call_get_connection_and_lock (pending=0x1010a978)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/dbus/dbus/dbus-pending-call.c:309<o:p></o:p> ------<o:p></o:p> (gdb) p *(DBusPendingCall *) 0x1010a978<o:p></o:p> $4 = {refcount = {value = 269547592}, slot_list = {slots = 0x10003fb4, n_slots = 0}, function = 0, connection = 0x0,<o:p></o:p>   reply = 0xffffffff, timeout = 0x0, timeout_link = 0x0, reply_serial = 4294967295, completed = 0, timeout_added = 1}<o:p></o:p>  (gdb) x/16 0x1010a978<o:p></o:p> 0x1010a978:     0x1010f848      0x10003fb4      0x00000000      0x00000000<o:p></o:p> 0x1010a988:     0x00000000      0xffffffff      0x00000000      0x00000000<o:p></o:p> 0x1010a998:     0xffffffff      0x73000000      0x00000000      0x00000011<o:p></o:p> 0x1010a9a8:     0x636f6e6e      0x65637469      0x6f6e0010      0x00000019<o:p></o:p> ------<o:p></o:p> #2  0x2d48c0ac in reply_handler_timeout (data=0x1010a978)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/dbus/dbus/dbus-connection.c:3104<o:p></o:p> ---------<o:p></o:p> (gdb) p *(DBusPendingCall *)data<o:p></o:p> $21 = {refcount = {value = 269547592}, slot_list = {slots = 0x10003fb4, n_slots = 0}, function = 0, connection = 0x0,<o:p></o:p>   reply = 0xffffffff, timeout = 0x0, timeout_link = 0x0, reply_serial = 4294967295, completed = 0, timeout_added = 1}<o:p></o:p> ---------<o:p></o:p> #3  0x2ce45ddc in timeout_handler_dispatch (data=0x0)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/dbus-glib/dbus/dbus-gmain.c:343<o:p></o:p> <o:p> </o:p> #4  0x2d1e6e98 in g_timeout_dispatch (source=0x1010f0f0, callback=0x2ce45db0 <timeout_handler_dispatch>,<o:p></o:p>     user_data=0x1010b610) at /nobackup/spuddupa/nmm32/contrib/glib/glib/gmain.c:3293<o:p></o:p> #5  0x2d1e2a00 in IA__g_main_context_dispatch (context=0x1010c9f8)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/glib/glib/gmain.c:1934<o:p></o:p> #6  0x2d1e531c in g_main_context_iterate (context=0x1010c9f8, block=1, dispatch=1, self=0x1010b610)<o:p></o:p>     at /nobackup/spuddupa/nmm32/contrib/glib/glib/gmain.c:2565<o:p></o:p> #7  0x2d1e5808 in IA__g_main_loop_run (loop=0x1010b3b0) at /nobackup/spuddupa/nmm32/contrib/glib/glib/gmain.c:2769<o:p></o:p> #8  0x10002cc4 in ThreadMainLoop (ptr=0x0) at infra/sysmgr/examples/./src/sysmgr_test.c:298<o:p></o:p> #9  0x2d20b3cc in g_thread_create_proxy (data=0x0) at /nobackup/spuddupa/nmm32/contrib/glib/glib/gthread.c:561<o:p></o:p> #10 0x2dfc19e8 in start_thread (arg=0x0) at pthread_create.c:256<o:p></o:p> #11 0x2e1b0334 in __thread_start () from /nobackup/spuddupa/nmm32/linkfarm/mips32/lib32/libc.so.6<o:p></o:p> Backtrace stopped: frame did not save the PC<o:p></o:p> <o:p> </o:p> Am I missing any initialization in the code above?<o:p></o:p> Is it ok to use the default GMainContext when creating the g_main_loop ?<o:p></o:p> In most of the examples for g_main_loop I see it being the last statement of the main program. However I am running it from a gthread. Is this ok?<o:p></o:p> <o:p> </o:p> Are there any known memory corruption issues that were fixed in newer releases of dbus and dbus-glib<o:p></o:p> Any suggestions in debugging this issue would be greatly appreciated.<o:p></o:p> <o:p> </o:p> Note: Will post the same mail on Upstart mailing list as well.<o:p></o:p> <o:p> </o:p> Thanks,<o:p></o:p> Sandeep<o:p></o:p> </div> </body> </html>