On 03/28/2018 07:20 PM, Pintu Kumar wrote: > On Wed, Mar 28, 2018 at 8:37 PM, Philippe Gerum <[email protected]> wrote: >> On 03/28/2018 09:54 AM, Pintu Kumar wrote: >>> Hi, >>> >>> We are facing one issue on Xenomai-3 on x86_64 system. >>> Kernel: 4.9.51 >>> ipipe version: 4 >>> # /usr/xenomai/sbin/version >>> Xenomai/cobalt v3.0.6 -- #5956064 (2018-03-20 12:13:33 +0100) >>> >>> Its a very simple API level test. >>> We create a condition variable and wait for the condition inside a task. >>> Then, we immediately signal the condition from the main thread, and simply >>> wait for the test to finish. >>> >>> But we observed that condition task is never getting released, and the >>> program hangs. >>> >>> This is the output: >>> -------------------------- >>> # ./condsignal >>> cond_task --> started >>> main --> cond signal success: 0 >>> Waiting for task to finish.... >>> ^C >>> >>> >>> This is the code snippet that was used. >>> ----------------------------------------------------- >>> # cat condsignal.c >>> >>> /* >>> * 1. Create an condition variable and wait inside a task. >>> * 2. Delete the condition variable from main task. >>> * 3. Observe that the condition wait is released and task ends normally. >>> * 4. Finally main task should exit normally. >>> * >>> * */ >>> #include <stdio.h> >>> #include <stdlib.h> >>> #include <sys/mman.h> >>> #include <alchemy/task.h> >>> #include <alchemy/mutex.h> >>> #include <alchemy/cond.h> >>> #include <alchemy/task.h> >>> >>> static RT_COND cond; >>> static RT_MUTEX mutex; >>> >>> static void cond_task(void *cookie) >>> { >>> int err; >>> >>> printf("%s --> started \n", __func__); >>> rt_mutex_acquire(&mutex, TM_INFINITE); >>> err = rt_cond_wait(&cond, &mutex, TM_INFINITE); >>> rt_mutex_release(&mutex); >>> if (err) { >>> printf("rt_cond_wait failed, err = %d", err); >>> return; >>> } >>> printf("%s --> cond wait done\n", __func__); >>> } >>> >>> int main(int argc, char **argv) >>> { >>> int err; >>> RT_TASK task1; >>> >>> mlockall(MCL_CURRENT | MCL_FUTURE); >> >> The line above is redundant with libcobalt inits. But you need: >> >> err = rt_task_shadow(NULL, "main", <prio>, 0); >> ... > > OK thank you so much for this. I will try it. > And, yes I am debugging this issue. > I found that rt_cond_wait_timed, did not return from here:
Ok, thanks for looking at this. The issue is that the app is missing the call to rt_task_shadow() in the main thread. So that thread receives -EPERM from rt_mutex_acquire(), and the rest is a fallout of that original error. -- Philippe. _______________________________________________ Xenomai mailing list [email protected] https://xenomai.org/mailman/listinfo/xenomai
