# Kernel crashed when calling vTaskDelay() before starting scheduler

**URL:** <https://forums.freertos.org/t/kernel-crashed-when-calling-vtaskdelay-before-starting-scheduler/15495>\
**Category:** Kernel\
**Created:** [July 19, 2022, 2:53pm UTC](https://forums.freertos.org/t/kernel-crashed-when-calling-vtaskdelay-before-starting-scheduler/15495 "2022-07-19T14:53:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ChiTran](https://avatars.discourse-cdn.com/v4/letter/c/7ab992/32.png) [@ChiTran](https://forums.freertos.org/u/ChiTran)\
**Post date:** [July 19, 2022, 2:53pm UTC](https://forums.freertos.org/t/kernel-crashed-when-calling-vtaskdelay-before-starting-scheduler/15495/1 "2022-07-19T14:53:13Z")

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Hi,

I’m facing a crash issue when my program unintendedly calls vTaskDelay() before the application starts the scheduler (calling vTaskStartScheduler). Is it an expected behavior?  
I attach my call stack so that people can get deeper inside the code.

 ![FreeRTOS-bug](https://d2v6vdsk2p900z.cloudfront.net/original/2X/1/1d14d99aff9338001e3e4619f18589afa004b64e.png)

Regards,  
Chi Tran

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**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\
**Post date:** [July 19, 2022, 3:01pm UTC](https://forums.freertos.org/t/kernel-crashed-when-calling-vtaskdelay-before-starting-scheduler/15495/2 "2022-07-19T15:01:04Z")

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Yes, that is expected behaviour. There are no tasks running before the scheduler starts, so vTaskDelay() cannot switch to anything, and the kernel data structures might not even be initialised. Checking if the scheduler is running in each API call would carry too much code size and run time penalty when the scheduler actually is running.

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<div class="post-metadata">

**Author:** ![ChiTran](https://avatars.discourse-cdn.com/v4/letter/c/7ab992/32.png) [@ChiTran](https://forums.freertos.org/u/ChiTran)\
**Post date:** [July 19, 2022, 3:04pm UTC](https://forums.freertos.org/t/kernel-crashed-when-calling-vtaskdelay-before-starting-scheduler/15495/3 "2022-07-19T15:04:08Z")

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It makes sense to me. Thank you so much.