Possible problem with CONFIGURE_MAXIMUM_SEMAPHORES succeeding

[Andrei Chichak]

Well ain't that a wtf?

I left in that define from when I was messing around with the TCP/IP shell.

That fixed it.

Thanks,
Andrei



On 2011-February-10, at 2:18 PM, Joel Sherrill wrote:

> On 02/10/2011 03:15 PM, Andrei Chichak wrote:
>> Hi all,
>> 
>> I was adding another semaphore to my code and decided to test the semaphore create failure case first. I added the create without incrementing the maximum number of semaphores that was configured. The create succeeded rather than failed.
>> 
>> I created 4 semaphores with the maximum set to 3. All returned rtems_status_code == 0. I set the maximum to 2, same. I set the maximum to 1, same. I set the maximum to 0, same result.
>> 
>> This is running on an Axiom CML5282 using RTEMS 4.9.4 and a BSP that is heavily based on the AV5282 and UC5282 BSPs.
>> 
>> Any ideas?
>> 
> Yep.  Many of the configuration parameters are "human friendly"
> and imply the configuration of more basic objects.
> 
> #define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 20
> 
> 
> /**
> *  From the number of file descriptors, we can determine how many
> *  semaphores the implementation will require.
> */
> #define CONFIGURE_LIBIO_SEMAPHORES \
>  (CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS + 1)
> 
> You need a mutex per open file plus one for the management
> of the collection.
>> 
>> I started stripping out code until my program generates this:
>> 
>> 
>> create sem1 semaphore returned with 0
>> 
>> create sem2 semaphore returned with 0
>> 
>> create sem3 semaphore returned with 0
>> 
>> create sem4 semaphore returned with 0
>> 
>> 
>> From this (only comments have been removed):
>> 
>> 
>> #include<rtems.h>
>> 
>> rtems_task Init(rtems_task_argument ignored);
>> 
>> #include<bsp.h>
>> 
>> #define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
>> #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
>> #define CONFIGURE_MAXIMUM_TASKS1
>> #define CONFIGURE_MAXIMUM_MESSAGE_QUEUES0
>> 
>> #define CONFIGURE_MAXIMUM_SEMAPHORES0
>> 
>> #define CONFIGURE_MAXIMUM_TIMERS0
>> #define CONFIGURE_MAXIMUM_PARTITIONS0
>> #define CONFIGURE_MAXIMUM_DRIVERS20
>> 
>> #define STACK_CHECKER_ON
>> 
>> #define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 20
>> 
>> #define CONFIGURE_RTEMS_INIT_TASKS_TABLE
>> #define CONFIGURE_INIT
>> 
>> #include<rtems/confdefs.h>
>> 
>> static rtems_id sem1;
>> static rtems_id sem2;
>> static rtems_id sem3;
>> static rtems_id sem4;
>> 
>> rtems_task Init(rtems_task_argument ignored) {
>> 
>> rtems_status_code status;
>> 
>> status = rtems_semaphore_create( rtems_build_name('S','E','M','1'),
>> 1,
>> RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL,
>> 0,
>> &sem1);
>> 
>> printk("create sem1 semaphore returned with %d\n", status);
>> 
>> status = rtems_semaphore_create( rtems_build_name('S','E','M','2'),
>> 1,
>> RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL,
>> 0,
>> &sem2);
>> 
>> printk("create sem2 semaphore returned with %d\n", status);
>> 
>> status = rtems_semaphore_create( rtems_build_name('S','E','M','3'),
>> 1,
>> RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL,
>> 0,
>> &sem3);
>> 
>> printk("create sem3 semaphore returned with %d\n", status);
>> 
>> status = rtems_semaphore_create( rtems_build_name('S','E','M','4'),
>> 1,
>> RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL,
>> 0,
>> &sem4);
>> 
>> printk("create sem4 semaphore returned with %d\n", status);
>> 
>> status = rtems_task_delete( RTEMS_SELF);
>> exit(0);
>> }
>> 
>> 
>> 
> 
> 
> -- 
> Joel Sherrill, Ph.D.             Director of Research&  Development
> joel.sherrill at OARcorp.com        On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>   Support Available             (256) 722-9985
> 
> 
>