[BUG] nrf9160 (Cortex-M33) with tickless enabled randomly locks up in ostest

[raiden00pl]

Description / Steps to reproduce the issue

nrf9160 (Cortex-M33) with tickless enabled randomly locks up in ostest (in random places).

Tested with config: ./tools/configure.sh nrf9160-dk/ostest_tickless

When tickless is disabled, the problem doesn't occur.
CONFIG_DEBUG_ASSERTIONS=y makes the problem not occur (or its harder to trigger).

The problem doesn't occur on release/12.6 (or its harder to trigger).

On which OS does this issue occur?

[OS: Linux]

What is the version of your OS?

Arch Linux

NuttX Version

nuttx-12.7.0-RC0, master

Issue Architecture

[Arch: arm]

Issue Area

[Area: Kernel]

Verification

• I have verified before submitting the report.

[raiden00pl]

most likely broken by #13283

[Fix-Point]

Currently I don't have a board to verify this. However, from the code, it seems to be a problem with the RTC tickless alarm driver. The function rtc_prepare_alarm in arch/arm/src/nrf91/nrf91_tickless_rtc.c may lose the next timer setting if the current time has exceeded the next time to be set.