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- Date: Mon, 28 Apr 2008 13:28:36 -0600
- From: daron.chabot at usask.ca (Daron Chabot)
- Subject: cdtest failure
Joel Sherrill wrote:
>> rying to run cdtest.exe (rtems cvs HEAD) in qemu (0.9.1) failed with
>> the following output:
>> djc at toolbox--
>> <http://rtems.rtems.org/mailman/listinfo/rtems-users>> qemu
>> -no-reboot -m 128 -boot n -tftp /opt/rtems/i386-
>> rtems/pc386/lib/rtems-4.9/tests -bootp /cdtest.exe -serial stdio
>> 2008-04-26 11:01:41.589 i386-softmmu KO
>> fatal error, exiting
>> EXECUTIVE SHUTDOWN! Any key to reboot...2008-04-26 11:01:59.995 i386-
>> softmmu KO
>> Inserting some instrumentation in "libcsupport/src/gxx_wrappers.c"
>> showed that the call to rtems_semaphore_create( ) was returning an
>> rtems_status_code of 5==RTEMS_TOO_MANY.
>> Changing CONFIGURE_MAXIMUM_SEMAPHORES from 1 to 2 in cdtest's
>> "system.h" permits the test to run to a successful conclusion.
>> Questions: "where is the other semaphore being consumed" ?? and
>> "what has changed to require more than a single semaphore" ??
> Breaking on rtems_semaphore_create will obviously
> answer the question but I recall that g++ added
> a second mutex in recent history.
> Can you double check where each create is called
> from before we add one? Just to make sure we are
> not covering up a shortage somewhere.
> It may make sense to add a "C++ application" configuration
> constant similar to the "NUMBER_OF_ADA_TASKS" one. That
> hides the ugly details of what C++ will actually use.
> I also distinctly recall adding a semaphore to the
> configuration in my local tree but obviously I threw
> that change away and didn't commit it. :(
> If you can explain this, it would really help.
> I am teaching 4 days this week and doing prep work today.
Solved: the mutex problem was of my own making :-(
I forgot that lately I have been configuring RTEMS (pc386 BSP) with
"USE_COM1_AS_CONSOLE=1". This configuration permits capture of RTEMS
stdout to a scrollable terminal window in Qemu (with the -serial stdio
command-line option), but it also must trigger the inclusion of an extra
mutex (termios?) beyond that required by c++.
Interestingly, using "objdump -S -D cdtest.exe" reveals calls to
"rtems_semaphore_create( )" in the following:
Given that rtems_gxx_mutex_init( ) consumes the sole semaphore
configured for the Workspace, why does printf(), used for
instrumentation in cdtest.exe, NOT require configuration for another
semaphore (i.e 2 in total)?
If I #define RTEMS_TEST_IO_STREAM in cdtest (to drag in cin/cout/cerr
machinery) I have to change CONFIGURE_MAXIMUM_SEMAPHORES from 2 (with
USE_COM1_AS_CONSOLE=1) to 5:
Is that one mutex for gxx_mutex_init, one for termios, and three for