bc669f9b13
Two related defects corrupt CDC-NCM transmit once TCP write buffers make TX bursty (a single txavail poll drains many queued segments back-to-back through cdcncm_send): 1. Buffer-reuse race. cdcncm coalesces datagrams into the single pre-allocated wrreq->buf that the USB controller transmits directly from, but cdcncm_send formatted a new NTB batch into it (cdcncm_transmit_format) without first waiting for the previous transfer to complete -- the wrreq_idle wait happened only later, in cdcncm_transmit_work. A new batch started while the previous NTB was still in flight overwrote the in-flight buffer, so the host dropped the corrupted NTB and TX could wedge (wrreq_idle never reposted). Fix: acquire wrreq_idle in cdcncm_send when starting a new batch (dgramcount == 0), before formatting; drop the now-redundant wait in cdcncm_transmit_work (a second wait on the init-to-1 semaphore would deadlock). 2. Concurrent transmit_work. cdcncm_send runs under the recursive netdev_lock and calls cdcncm_transmit_work() synchronously in the buffer-full branch, while a scheduled delaywork instance runs cdcncm_transmit_work() on ETHWORK -- two different threads. Two EP_SUBMITs of the one wrreq corrupt the IN request queue and leave the IN buffer prepared-but-unarmed (controller idle, wrreq_idle never reposted). Fix: wrap cdcncm_transmit_work in netdev_lock (the synchronous caller already holds this recursive nxrmutex; a delaywork instance blocks until the drain releases it), and add an empty-batch guard (dgramcount == 0 -> return) so a delaywork that runs after a synchronous flush emptied the batch does not seal an empty NTB and double-submit the in-flight wrreq. Validated on RP2350 (Pico 2 W) with CONFIG_NET_TCP_WRITE_BUFFERS=y as part of the complete fix set: 144 dense/concurrent HTTP downloads, zero wedges, ~486 KB/s (previously transmit hung within a few requests). On RP2350 full stability under maximal TX density additionally requires a memory barrier between the BUFF_STATUS clear and the AVAILABLE re-arm in the Cortex-M33 USB device driver (a separate change); these cdcncm defects are real and the fixes correct independent of it. Signed-off-by: Ricard Rosson <ricard@groundbits.com> Assisted-by: Claude (Anthropic Claude Code) Signed-off-by: Ricard Rosson <ricard@groundbits.com> |
||
|---|---|---|
| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
Getting Started
First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.
Documentation
You can find the current NuttX documentation on the Documentation Page.
Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.
The old NuttX documentation is still available in the Apache wiki.
Supported Boards
NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.
Contributing
If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.
License
The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.