Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
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raiden00pl a3d4802ff8 drivers/serial: read the consumer index once in uart_recvchars()
Same issue as the previous commit, on the receive side: uart_read()
advances recv.tail from thread context without holding the critical
section, but the recvbuf batch path of uart_recvchars() reads recv.tail
several times (the full check, the watermark count and the free-space
computation).  If uart_read() moves and wraps the index in between, the
computed free space goes negative and is passed to recvbuf() as a huge
size_t, which lets the driver store past the end of the ring buffer.

Read recv.tail once per loop iteration and derive everything from that
snapshot.  The consumer only ever moves the index forward, so a stale
snapshot merely stores less now.

Assisted-by: Claude Code
Signed-off-by: raiden00pl <raiden00@railab.me>
2026-09-10 23:09:16 +08:00
.github tools/ci: remove obsolete testrun harness 2026-09-02 11:44:23 -03:00
arch arch/intel64: don't clear the oneshot handler from the HPET ISR 2026-09-10 10:23:46 +08:00
audio audio: limit the buffer count guard to shared ring requests 2026-08-05 07:58:53 +02:00
binfmt libs/libc/elf, binfmt: Describe the GOT by base and size, not by index. 2026-09-08 16:31:16 -03:00
boards boards/esp32s3-xiao: wire up Wi-Fi, guarding PM light sleep during radio init 2026-09-10 10:23:15 +08:00
cmake cmake: Build FDPIC modules the way the make build does. 2026-09-09 10:21:21 +08:00
crypto tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
Documentation tools/refresh.sh: Fix multi-argument parsing 2026-09-10 16:26:53 +02:00
drivers drivers/serial: read the consumer index once in uart_recvchars() 2026-09-10 23:09:16 +08:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs libs/libc/elf: Place an FDPIC object's segments independently. 2026-09-08 16:31:16 -03:00
graphics graphics/nxterm: consume SGR escape sequences 2026-08-23 10:46:02 +08:00
include libs/libc/elf, binfmt: Describe the GOT by base and size, not by index. 2026-09-08 16:31:16 -03:00
libs arch/arm, libs/libc/elf: Build FDPIC modules in the normal ELF build. 2026-09-09 10:21:21 +08:00
mm cmake: Use NUTTX(_DIR/_BIN_DIR) instead CMAKE(_SRC_DIR/_BIN_DIR) 2026-08-09 11:13:08 -03:00
net net/tcp: add configurable delayed ACK threshold 2026-09-08 09:00:19 +08:00
openamp cmake: Use NUTTX(_DIR/_BIN_DIR) instead CMAKE(_SRC_DIR/_BIN_DIR) 2026-08-09 11:13:08 -03:00
pass1 tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
sched sched/environ: Serialize clearenv updates. 2026-09-09 10:22:01 +08:00
syscall fs: rename PSEUDOFS_SOFTLINKS to FS_LINKS 2026-08-27 01:12:33 +08:00
tools tools/refresh.sh: Fix multi-argument parsing 2026-09-10 16:26:53 +02:00
video video/videomode: Fix EDID parsing and formatting of video mode dumps 2026-08-29 11:09:11 -03:00
wireless wireless/bluetooth: fix inverted MTU cap in bt_conn_send() 2026-08-30 10:48:18 -03:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines arch/arm: Reserve r10 via ARCHCFLAGS and hoist the PIC module flags. 2026-07-24 23:09:08 +08:00
.codespellrc Revert "zbus: Add linker support and documentation for the zbus port" 2026-08-30 10:45:19 -03:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore boards/risc-v/eic7700x: Adopt the common board layout. 2026-08-19 01:40:57 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint feat: add a GitHub action to lint the YAML files 2020-12-15 09:52:04 -06:00
AUTHORS AUTHORS: add Jorge Guzman 2026-08-25 08:43:13 -04:00
CMakeLists.txt arch, boards, cmake: Build C++ ELF modules without __cxa_atexit. 2026-09-04 15:44:24 -03:00
CONTRIBUTING.md contributing: Add requirement for 'Assisted-by' commit field 2026-07-12 09:42:28 +08:00
INVIOLABLES.md INVIOLABLES.md: Fix a simple alignment and change occurrences of Nuttx 2020-09-03 01:33:05 +08:00
Kconfig include/nuttx: Add link-time iterable sections infrastructure 2026-08-27 01:04:05 +08:00
LICENSE libs/libdsp: Add Matrix operations 2026-07-11 14:55:59 -03:00
Makefile !boards: enforce secure ROMFS passwd and TEA key setup 2026-07-09 22:41:11 +08:00
NOTICE Remove the double blank line from source files 2022-02-20 20:10:14 +01:00
README.md ci/testing: Add MemBrowse Integration 2026-06-18 12:07:41 -03:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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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.