clock_gettime(CLOCK_MONOTONIC) reads g_system_ticks, which is only
refreshed when a timer expiration is processed. On SCHED_TICKLESS an
idle system has no timeout armed, so the clock returns 0 before the
first expiration and a frozen value afterwards.
This regressed in commit c7b6442974, which switched CLOCK_MONOTONIC to
the sched tick counter to exclude suspended time. Excluding suspend time
needs explicit accounting maintained by PM code, the tick counter cannot
provide it on tickless.
Restore the live read. On non-tickless builds clock_systime_timespec()
falls back to the same tick counter, so behavior there is unchanged.
Verified on qemu-intel64, nrf52840-dk and rv-virt.
Signed-off-by: raiden00pl <raiden00@railab.me>
Assisted-by: Claude Code
612f9a07dd