FelipeMdeO opened a new pull request, #20024:
URL: https://github.com/apache/nuttx/pull/20024
## Summary
`CONFIG_ESP32S3_TICKLESS` hangs forever the first time a task sleeps
with a fractional-second timeout of ~134ms or more (e.g.
`usleep(500000)`) while another task also has a pending timeout —
e.g. `apps/testing/ostest` hangs immediately, since that's exactly
what `user_main()`'s first statement does.
## Root cause
```c
#define NSEC_2_CTICK(nsec) (((nsec) * CTICK_PER_USEC) / NSEC_PER_USEC)
```
`nsec` is a 32-bit `long` and `CTICK_PER_USEC` is 16 (16MHz systimer),
so `nsec * 16` overflows a 32-bit signed int for `tv_nsec >= ~134ms`.
The overflowed (negative) result gets added into `up_timer_start()`'s
`uint64_t cpu_ticks`, wrapping to a value near `UINT64_MAX`. The
systimer alarm then gets programmed that many ticks in the future —
effectively never — so the sleeping task never wakes up.
`SEC_2_CTICK`/`USEC_2_CTICK` have the same class of bug at higher
thresholds.
## Fix
Cast to `uint64_t` before multiplying in all three macros, forcing
64-bit arithmetic (matching the already-safe `CTICK_2_*` macros).
Also fixed a pre-existing nxstyle nit (missing blank line) in
`tickless_isr()`, next to the changed code.
## Testing
Board: Seeed XIAO ESP32-S3, built on current `master`.
- Reproduced: instrumented `up_timer_start()` and confirmed the exact
overflow (`cpu_ticks=18446744073709121682` for a ~500-700ms sleep).
- Before: `ostest` (`CONFIG_ESP32S3_TICKLESS=y`) hangs right after
`Started user_main`, reproducible every time from a clean flash.
- After: full `ostest` suite runs past that point and completes.
- Plain single-task sleeps (`sleep 3` from NSH) keep correct timing
before and after (3.06s measured).
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