RIOT-2022.01 - Release Notes

RIOT is a multi-threading operating system which enables soft real-time
capabilities and comes with support for a range of devices that are typically
found in the Internet of Things: 8-bit and 16-bit microcontrollers as well as
light-weight 32-bit processors.

RIOT is based on the following design principles: energy-efficiency, soft
real-time capabilities, small memory footprint, modularity, and uniform API
access, independent of the underlying hardware (with partial POSIX compliance).

RIOT is developed by an international open-source community which is
independent of specific vendors (e.g. similarly to the Linux community) and is
licensed with a non-viral copyleft license (LGPLv2.1), which allows indirect
business models around the free open-source software platform provided by RIOT.

About this release

The 2022.01 release brings support for new packages, new boards and drivers,
as well as several package upgrades and bug fixes. Among others, this release
improves the RIOT codebase with:

Rust support

RIOT now offers convenient integration of Rust application programming, with
wrappers interfacing to RIOT modules such as timers, network stack.

Improved timers

Many modules have migrated from using xtimer to our more power-efficient
alternative ztimer. Also, ztimer64 was introduced, which enables
a drop-in replacement for all of xtimer features.

Kconfig support

Kconfig modeling coverage is significantly extended. Nearly all supported
boards are now modeled with Kconfig.

Summary:

436 pull requests, composed of 1159 commits, have been merged since the
last release, and 11 issues have been solved. 43 people contributed with
code in 88 days. 2475 files have been touched with 44925 (+) insertions and
14687 deletions (-).

Notations used below

+ means new feature/item
* means modified feature/item
- means removed feature/item

New features and changes

Full list available at https://github.com/RIOT-OS/RIOT/milestone/37?closed=1

Core

core/include/kernel_defines.h: add index_of() macro (#17142)
core: Add IS_CT_CONSTANT() (#17273)
core: add WITHOUT_PEDANTIC() and DECLARE_CONSTANT() (#17176)

core: Warn about using irq_enable (#17433)
core: make SCHED_TEST_STACK boolean and default to 1 with DEVELHELP (#17132)

System Libraries

sys/architecture: add HAS_ALIGNMENT_OF() helper (#17177)
sys/arduino: add assertion to gpio handling (#17443)
sys/atomic_utils: add atomic_{load,store}_ptr() (#17256)
sys/include/event/periodic: add count (#17276)
sys/isrpipe: add isrpipe_write (#17336)
sys/sched_rr: Add a round robin scheduler module (#16126)
sys/stdio: add optional function stdio_available (#17446)
sys/test_utils/result_output: add sort to multiple output check (#17269)
sys/tsrb: add peek functions (#17266)
sys/tsrb: add tsrb_clear (#17337)
sys/ztimer: add 'ztimer_no_periph_rtt' (#17284)
sys/ztimer: add some best practices (#17370)
sys/ztimer: ztimer_now() add warning regarding comparing now() values (#17404)
usb/hid: Add HID report descriptor defines (#17242)
sys/arduino: add Serial over stdio support (#17447)
sys: introduce sysclk function to retrieve core clock frequency (#17342)
sys/new_delete: add malloc/free based new/delete implementation (#17464)

event/timeout: remove forced ZTIMER_USEC dependency (#16958)
riotboot_dfu: use ztimer instead of xtimer (#17051)
riotboot_serial: enter bootloader mode by pin (#17248)
schedstatistics: Convert to ztimer (#17216)
stdio_rtt: Convert to ztimer (#17122)
stdio_semihosting: Convert to ztimer (#17123)
sys/can: migrate to ztimer (#17366)
sys/cpp11-compat: use new/delete operators from sys/cpp_new_delete (#17475)
sys/evtimer: use now returned by set (#17394)
sys/fmt: make fmt_s32_dfp() string based (#17106)
sys/Makefile.dep: fix event periodic dependency (#17318)
sys/picolibc_syscalls_default: support new picolibc stdio globals (#17001)
sys/random: default to musl LCG instead of TinyMT (#17188)
sys/suit: adjust dependencies for CoAP transport (#17182)
sys/test_utils/result_output/json: optional space after symbol (#17034)
sys/turo: Allow default selection of json (#17039)
sys/ztimer/xtimer2ztimer.cocci: extend and fix api replacements (#17234)
sys/ztimer64: default select ztimer64_init (#17414)
sys/ztimer64: make _del_entry_from_list() safe for uninit ztimer64_t (#17368)
sys/ztimer: remove double ztimer indirection (#17272)
sys/ztimer: ztimer_remove report success (#17408)
usbus/cdc_acm: Return stall on line coding not supported (#17085)
usbus/hid: fix ep_out readiness (#17230)
usbus/hid: fix ep_out readiness (#17245)
usbus: Bind extra USB config (#17380)
usbus: check received setup request data amount (#17203)
sys/ztimer64: initial PR (#16928)

Networking

gnrc_pktbuf_cmd: add od dependency with gnrc_pktbuf_static (#17228)
sys/net/dhcpv6: Add stateless DHCPv6 (#16731)
sys/net: Add ipv4/ipv6 pseudomodules (#16966)
sys/shell/sc_nimble_netif: add ping subcommand (#16539)

dsm: rename DTLS_PEER_MAX and make it dependent on
CONFIG_DTLS_PEER_MAX (#16967)
gcoap_dtls: destroy session in _tl_send only on connection errors (#16963)
gnrc_dhcpv6_client / uhcp: delay router advertisements until prefix
was received (#16755)
gnrc_gomach: adapt duty recording parameters' namings. (#8954)
gnrc_netif: move netdev initialization to ops->init (#16918)
lwip: bump to v2.1.3 (#16774)
net/gcoap: port to ztimer (#17141)
nimble/statconn: use errno return values (#17344)
pkg/lwip: Don't control IPv6 via IPv4 flag (#17175)
pkg/lwip: Fix dualstack build when only using 6lowpan (#17174)
pkg/openthread: bump version to 20200818 + adapt to use CMake to
configure the build (#16948)
pkg/openthread: migrate to ztimer (#17120)
pkg/paho-mqtt: migrate to ztimer (#17143)
pkg/semtech-loramac: fix get/set dr command (#17117)
sys/evtimer,ztimer: do not depend on ztimer_now64 (#17357)
sys/net/gnrc: fix compilation with -Wcast-align (#17157)
sys/shell/gnrc_netif: Allow 'ifconfig help' (#17006)
test/ieee802154_hal: general cleanup and cosmetic fixes (#16913)
tests/lwip_sock: Take lock before calling etharp (#17145)
socket_zep: port to radio HAL (#16932)
ieee802154/hal: adapt to latest changes of #13943 (#16946)

Packages

pkg/lz4: add support for LZ4 compression/decompression (#17178)
pkg/uzlib: add support for zlib compression/decompression (#17179)
pkg: add support for Elk Tiny Javascript engine (#16887)
pkg: add support for FreeRTOS coreJSON library (#16997)
pkg/arduino_sdi_12: add SDI-12 for Arduino as package (#16587)

hacl: Switch git address to RIOT-OS-pkgmirror (#16941)
make: support package mirrors (#16927)
pkg/emlearn: bump to 0.12 (#16937)
pkg/jerryscript: bump to 2.4.0 (#16938)
pkg/mynewt-core/patches: silence cast-align (#17397)
pkg/qr-code-generator: bump to 1.7.0 (#16939)
pkg/uwb-core: fix wrong header include (#17345)
pkg/uwb-core: enable frame filtering, allow usage of common event thread (#17264)
pkg/wakaama: use ztimer (#17103)
pkg/arduino_sdi_12: support the remote-revb board (#17119)
pkg/fatfs: bump version to r0.14b (#16412)
Update tiny-asn1 package (#16936)
pkg/lvgl: use ztimer instead of xtimer (#17031)
pkg: migrate some packages to ztimer (#17309)

Boards

boards/feather-m0: add arduino feature (#17401)
boards/iotlab-m3: add MTD definition (#17339)
boards/nrf9160dk: add riotboot support (#17226)
boards/nucleo-g431rb: added PWM configuration (#17030)
boards/p-l496g-cell02: add riotboot feature (#17463)
boards/stm32f469i-disco: Add DAC (#17214)
boards/stm32g031-disco,examples,tests: Added STM32G031-DISCO board (#16959)
boards: add board support for Alientek Pandora (#17259)
boards: add support for stm32f746g-disco (#17198)

boards/common/microbit: fix doxygen grouping (#17440)
boards/esp* and cpu/esp: feature definition cleanup (#17438)
boards/lora-e5-dev: enable 3.3V and 5V output by default (#17158)
boards/lora-e5-dev: fix default DARWIN port (#17373)
boards/stm32f469i-disco: Create board (#16898)
boards/{calliope-mini,microbit*}: factorize common microbit module,
use ztimer (#17124)
boards: cpu: replace GPIO_UNDEF by SPI_CS_UNDEF in SPI configuration (#17468)
boards: model nrf52 boards (#17299)
boards: unify user button defines (#17428)
tools/elf2uf2: addition of new PROGRAMMER for RPi-pico (#17348)

CPU

Add some Rust building infrastructure and example (#16274)
cpu/esp32: add clear bus during init to the I2C software
implementation (#17346)
cpu/nrf9160: add periph_flashpage support (#17225)
cpu/stm32: Add hardening changes to stm32 (#16979)
nimble_scanner: rework to enable scanning BLE5 PHYs and extended
advertisements (#16843)
nrf5x_common: Add qdec peripheral implementation (#17201)
cpu/esp32: Add openocd programming support (#16911)
cpu/stm32: add driver for the LTDC peripheral (#17437)
cpu/stm32: add new usbdev FS support (#17281)
cpu/stm32: add support for U5 family (#17410)

boards/common/esp8266: Set RTS and DTR to 0 on pyterm. (#16305)
cc2538_rf: remove RX Busy detection in request_set_trx_state (#16821)
cpu/arm7_common: suppress false positives of cppcheck (#17218)
cpu/atmega_common: make cppcheck happy (#17219)
cpu/atmega_common: Remember CTC mode with timer_periodic (#17387)
cpu/atxmega/include/cpu_conf: ztimer64 arithmetic idle stack fix (#17362)
cpu/cortexm_common: make CI happy (#17220)
cpu/esp32: make CI happy (#17221)
cpu/esp32: place freertos and periph in IRAM (#17087)
cpu/esp32: support CPU clocks 2 MHz and 40 MHz (#17413)
cpu/esp: change dynamic SSID option handling (#17415)
cpu/esp: migrate to ztimer (#17386)
cpu/kinetis/include: fix xtimer backend timer selection (#17393)
cpu/native/include: other stacksizes based on default (#16956)
cpu/native: migrate periph_rtc to ztimer (#17125)
cpu/qn908x: migrate ADC periph to ztimer (#17321)
cpu/sam0_common: SPI: don't perform DMA transfer for small buffers (#16926)
cpu/sam0_common: uart: set oversampling based on baud rate (#17186)
cpu/stm32/include/cpu_conf_stm32_common.h: fix typo in macro (#17187)
cpu/stm32: bump cmsis repositories to latest releases + extend CPU
models kconfig (#17293)
cpu/stm32: duplicated ADC devices definitions (#16968)
cpu/stm32: migrate adc and eth periphs to ztimer (#17320)
cpu/stm32: split periph_cpu.h in sub headers (#17441)
cpu: do not auto-select ztimer_periph_rtt for sam0, fe310 (#17395)
drivers/periph: use uint_fast8_t as default type (#17191)
esp8266: Download Espressif RTOS SDK as a new RIOT PKG (#16425)
periph/flashpage: extend API (#16972)
periph/flashpage: fix wrong doxygen group (#17202)
stm32/usbdev: Use ztimer instead of xtimer (#17047)
cpu/esp: compile optional modules in CI (#17314)
cpu/stm32/wl: initial periph_adc implementation (#17183)
cpu/stm32: enable USB OTG FS on high end L4 (#17302)

Device Drivers

drivers/dose: enable standby pin (#16752)
drivers/hm330x: initial commit (#16333)
drivers: add PCF857X I2C I/O expander driver (#10430)
drivers: only build saul interface if saul module is used + add
saul_drivers test application (#17470)
netdev: add netdev_register_signal (#16922)
drivers/ft5x06: add support for touch panel controller (#17448)
drivers/stmpe811: add spi mode (#17088)
drivers/dose: make use of UART collision detection feature (#16681)

driver/at30tse75x: port to ztimer_usec (#17137)
drivers/ads101x: migrate to ztimer (#17102)
drivers/ata8520e: migrate to ztimer (#17105)
drivers/atwinc15x0: migrate to ztimer (#17381)
drivers/bmp180: migrate to ztimer (#17101)
drivers/dose: calculate timeout based on symbol rate (#16768)
drivers/dsp0401: migrate to ztimer (#17110)
drivers/mhz19: migrate to ztimer (#17308)
drivers/rn2xx3: migrate to ztimer (#17112)
drivers/sdcard_spi: convert to ztimer_usec (#17361)
drivers/stmpe811: improve interrupt callback management (#17487)
drivers/xbee: migrate to ztimer_msec (#17114)
drivers: migrate mpu9x50 and si70xx to ztimer (#17358)
drivers: migrate some drivers to ztimer (#17315)
drivers: remove some useless xtimer includes (#17303)
drivers: several cleanups related to xtimer + some ztimer migration (#17375)
makefiles: remove PCF857x pseudomodule definitions (#17343)
drivers/periph_common: build periph module selectively (#17418)

Documentation

boards/lora-e5-dev: add warning in doc (#17185)
doc/getting-started.md: added beginner friendly instructions (#17050)
doc/rust: Add maintenance guidance (#17505)

boards/lora-e5-dev: extended documentation (#17244)
boards/stm32f746g-disco: extend documentation (#17310)
doc/.../getting-started.md: update software requirements (#17002)
doc/boards/rpi-pico: Addition of section concerning shell access (#17454)
doc: fix libcoap removal commit (#17378)
pkg/openwsn: update doc (#17131)
tools/zep_dispatch: document foren6 usage (#17326)
doc: fix missing or non matching arguments in Doxygen documentation (#17461)

Build System / Tooling

dist/tools/ci: add can_fast_ci_run.py (#17239)
dist/tools/doccheck/exclude_patterns: add new warnings (#17104)
dist/tools/doccheck: add create_pattern.sh (#17082)
make: add info-emulated-boards helper target (#16975)
Makefile.base: add SUBMODULES_NO_SRC to excluded a selected SUBMODULE
*.c (#17222)
tools/compile_and_test_for_board: apply black automatic code
formatter + add format checker in tox (#16905)
tools/insufficient_memory: add create_makefile.ci.sh and Makefile.ci
make target (#16109)
tools/pythonlibs/riotctrl_*: add code format check with black (#16915)
tools/zep_dispatch: add support for foren6 sniffer (#16879)
tools/zep_dispatch: add topology generator (#16889)
makefiles/cflags.inc.mk: Add -Wcast-align (#14955)

cppcheck: output all annotations as error (#17134)
dist/tools/coccinelle/force: remove static.cocci (#17139)
Makefile.include: remove warning about EXTERNAL_MODULE_DIRS API
change (#16984)
Makefile.include: rename Makefile.ci target to create-Makefile.ci (#17205)
makefiles/docker.inc.mk: pass TEST_KCONFIG (#17398)
murdock: make use of can_fast_ci_run.py (#17325)
static-tests: disable cppcheck (#17282)
tools/backport_pr: check code format with black (#16907)
tools: can_fast_ci_run.py: ignore comment changes for \.[ch]$ (#17405)

Kconfig

cpu/avr8: model kconfig (#16929)
cpu/efm32: model kconfig (#16912)
cpu/esp: integrate CPU clock frequency selection in Kconfig (#17424)
cpu/msp430: add Kconfig (#17290)
cpu/nrf52: initial kconfig modeling (no netif) (#16837)
cpu/nrf9160: add Kconfig dependencies (#17291)
cpu/riscv: model Kconfig (#16909)
makefiles/kconfig: add board & CPU config variables (#17376)
pkg/uwb*: add Kconfig dependency modelling (#16780)
sys/trace: migrate to ztimer and add Kconfig support (#17319)
.murdock: Add modules/pkgs diff of make/kconfig (#17094)
.murdock: Add nucleo boards to kconfig test (#16845)
.murdock: Add same54-xpro to kconfig tests (#17255)

.murdock: Kconfig test apps for all boards (#17402)
boards/adafruit-itsybitsy-m4: Model kconfig (#17331)
boards/feather-m0*: base board definition in Kconfig (#17445)
boards/samd21-based: model Kconfig (#17355)
boards/saml21-based: model kconfig (#17270)
boards/stm32-based: model Kconfig (#17374)
cpu/esp{32,8266}: model kconfig (#17232)
cpu/kinetis: model kconfig (#17235)
cpu/lpc23xx: model kconfig (#17279)
cpu/nrf51: model kconfig (#17274)
cpu/qn908x: model kconfig (#17277)
cpu/{cc26xx, cc13xx}: model kconfig (#17236)
drivers/sx126x/Kconfig: rework model selection (#17289)
sys/benchmark/kconfig: cleanup ztimer dependency (#17317)
sys/log: model Kconfig (#17286)
sys/vfs: model Kconfig (#17287)

Examples

example/gcoap: add LWIP make option (#17130)

examples/gcoap: split client and server implementation (#17471)
examples/gnrc_networking_subnets: remove broken symlink (#17389)
examples/lorawan: use ztimer_msec if not rtc (#17181)
examples/gnrc_networking: cleanup and static function declarations in
udp.c (#17384)

Testing

pkg/fff: Add fake functions framework package (#17076)
murdock: add some doc on how to efficiently limit builds (#17312)
tests/bench_ztimer: add port of bench_xtimer (#17391)
tests/pkg_ucglib: add missing function declaration (#17347)

gh/workflows/release-tests: update LoRaWAN parameters to ttnv3 (#17009)
gha/workflows/release-test: set python version to 3.8 (#17038)
tests/*: Fix nightly failures due to f-string (#17283)
tests/malloc: fix counting bugs (#17323)
tests/periph_adc: migrate to ztimer (#17322)
tests/periph_timer_periodic: spice up test (#17388)
tests/unittests/tests-base64: enlarge test buffer for worst case (#17292)
test/pkg_u8g2: increase main stacksize for SDL (#16954)
tests/pkg_fatfs{_vfs}: drop whitelist (#17478)
Fix some cppcheck errors (#17271)

API Changes

core/kernel_defines.h: drop ALIGN_OF() (#17267)
core/kernel_defines: drop BUILD_BUG_ON() (#17268)
core/msg: make msg_avail() return 0 on no queue (#17262)
cpu: call cpu_init() from startup code, not from board (#16055)
drivers/periph_i2c: let i2c_acquire return void (#17275)
sys/ztimer: ztimer_set() return the now value (#17385)
USB: refactor to xmit-based API (#17064)

Deprecations

Deprecations (2)

cpu/mips: deprecate mips cpu (#17304)
sys/include/xtimer.h: deprecate nanosleep (#17296)
sys/include/evtimer.h: deprecate evtimer_now_min (#17357)
usbdev/USBUS: deprecate transfer failure reporting report (#17046)

Removals (9)

boards/fox: remove BOARD (#17021)
dist/iotlab: remove deprecated auto-ssh backward compatibility (#17476)
drivers/ethos: remove deprecated USE_ETHOS_FOR_STDIO define (#17499)
make: remove deprecation warnings raised with flasher tools old vars (#17490)
pkg/libcoap: remove (#17163)
sys/asymcute: remove deprecated CONFIG_ASYMCUTE_BUFSIZE_EXP (#17481)
sys/crypto: remove deprecated CIPHER_AES_128 (#17480)
sys/saul_reg: remove deprecated saul_reg_rm function (#17489)
sys/shell: remove deprecated SHELL_NO_{ECHO,PROMPT} defines (#17484)

Bug fixes (66)

cpu/native: add -no-pie to LINKFLAGS (#16186)
boards/adafruit-clue: use internal RC oscillator (#17069)
boards/feather-m0-*: fix Arduino feature in Kconfig (#17444)
boards/nrf9160dk: fix LED macros (#17328)
boards/nucleo-g07xrb: fix or exclude some doxygen warnings (#17079)
boards/nucleo-g07xrb: fix or exclude some doxygen warnings [backport
2021.10] (#17084)
boards/stm32f723e-disco: use connect_assert_srst with openocd (#17462)
boards/stm32f746g-disco: use connect_assert_srst with openocd (#17449)
boards/stm32f769i-disco: fix and cleanup default configuration (#17199)
cdc_ecm: Truncate frames at max ethernet size (#17200)
cpu/atmega1281: fix pcint (#17227)
cpu/esp*: small documentation fixes (#17456)
cpu/esp32: fix esp_wifi_enterprise compilation problem (#17306)
cpu/esp8266: fix problems with ESP WiFi and migration to ztimer (#17427)
cpu/esp8266: place freertos functions in IRAM (#17080)
cpu/esp: revert the change for default definition of ESP_WIFI_PASS (#17420)
cpu/esp_common: fix unaligned access in periph_flashpage (#17150)
cpu/native: align stack in thread_stack_init() (#17155)
cpu/sam0: prevent disabled irq from being called (#17007)
cpu/stm32/periph/usbdev: fix alignment issues (#17154)
cpu/stm32: clone cmsis header in build/stm32 (#17212)
dhcpv6_client: keep integers in retransmission calculations signed (#16992)
doc: fix the reference to libcoap removal commit in LOSTANDFOUND.md (#17371)
driver/css811: fix read status (#17340)
drivers/ccs811: fix of documentation (#17169)
drivers/dht: correct interpreting raw values (#16934)
drivers/dose: fix standby mode (#17184)
drivers/encx24j600: fix unaligned memory access (#17156)
drivers/lis3dh: fix unaligned memory access (#17149)
drivers/sx126x: fix sync word and TX PA configuration (#17138)
ethos: move bulk of state machine out of ISR context (#17265)
Fix NDEBUG compilation problems (#14364)
gnrc_ipv6_nib: queue packets that trigger probing on border router (#16947)
ieee802154 / tests/unittests: fix all-asan reported errors (#17329)
Makefile.base: cleanup non selected source object files (#16945)
Makefile.base: do not clean objects of bindist modules (#16981)
makefile.dep: require arch_% cpu_core_% features first (#17224)
murdock: don't run can_fast_ci_run if FULL_BUILD==1 (#17495)
nimble: fix nimble_scanner regression bugs (#17334)
pkg/arduino_sdi_12: fix for the feather-m0 board (#17501)
pkg/ccn-ndn: migrate to ztimer (#17377)
pkg/littlefs{,2}: fix compilation with -Wcast-align (#17151)
pkg/nimble: version bump to fix broken scanning (#16960)
pkg/paho-mqtt: fix memory corruption (#17503)
pkg/relic: bump to current master (#17161)
pycrypto: use pycryptodome instead (#17107)
SECURITY.md: fix broken email reference (#17118)
shell/gnrc_icmpv6_echo: Fix hang with no msg queue (#17261)
sys/fido2: fix CBOR parsing (#17192)
sys/fido2: fix CBOR parsing [backport 2021.10] (#17193)
sys/net/dns: mark dns_hdr_t as packed (#17153)
sys/net/fib: fix compilation with -Wcast-align (#17194)
sys/net/gcoap: Use socket _buf API to recognize truncated requests (#16378)
sys/posix/socket: align struct sockaddr{,_storage} (#17152)
sys/posix/socket: use explicit bind (#16852)
sys/test_utils/result_output: fix turo_float() precision value (#17036)
sys/ztimer/kconfig: enable xtimer compat only with timer backend (#17307)
sys/ztimer: don't access non-existent timer (#17409)
sys/ztimer: don't default to rtc for ztimer_sec (#17113)
sys/ztimer: fix backend selection (#17372)
tests/socket_zep: fix automatic test (#17432)
tests/unittests: fix unaligned access (#17195)
tools/openocd: check OPENOCD_VERIFY after IMAGE_OFFSET is computed (#17251)
tools/zep_dispatch: forward based on source addr, not MAC addr (#16957)
turo: some json fixes (#17027)
usbus/dfu: fix underflow condition while updating firmware (#17128)

Known issues

Network related issues (53)

6lo gnrc fragmentation expects driver to block on TX (#7474)
6lo: RIOT does not receive packets from Linux when short_addr is set (#11033)
Address registration handling inappropriate (#15867)
app/netdev: application stops working after receiving frames with
assertion or completely without error (#8271)
at86rf2xx: Dead lock when sending while receiving (#8242)
at86rf2xx: lost interrupts (#5486)
CC2538 RF overlapping PIN usage (#8779)
core: "Invalid read of size 4" (#7199)
cpu/esp8266: Tracking open problems of esp_wifi netdev driver (#10861)
dist/tools/sliptty/start_network.sh: IPv6 connectivity is broken on
PC (#14689)
driver/mrf24j40: blocks shell input with auto_init_gnrc_netif (#12943)
drivers/at86rf215: Incorrect channel number set for subGHz (#15906)
DTLS examples cannot send message to localhost (#14315)
Emcute cannot create a double-byte name (#12642)
ethernet: Missing multicast addr assignment (#13493)
ethos: fails to respond to first message. (#11988)
ethos: Unable to choose global source address. (#13745)
ethos: Unable to handle fragmented IPv6 packets from Linux kernel (#12264)
examples/cord_ep: Dead lock when (re-)registering in callback
function (#12884)
examples/gnrc_border_router: esp_wifi crashes on disconnect (#14679)
Forwarding a packet back to its link layer source should not be
allowed (#5051)
gcoap example request on tap I/F fails with NIB issue (#8199)
gcoap: Suspected crosstalk between requests (possible NULL call) (#14390)
General 802.15.4/CC2538 RF driver dislikes fast ACKs (#7304)
gnrc ipv6: multicast packets are not dispatched to the upper layers (#5230)
gnrc_border_router stops routing after a while (#16398)
gnrc_icmpv6_echo: flood-pinging another node leads to leaks in own
packet buffer (#12565)
gnrc_ipv6: Multicast is not forwarded if routing node listens to the
address (#4527)
gnrc_rpl: missing bounds checks in _parse_options (#16085)
gnrc_rpl: nib route not updated when topology / DODAG changes (#17327)
gnrc_sock_udp: Possible Race condition on copy in application buffer (#10389)
gomach: Resetting netif with cli doesn't return (#10370)
ieee802154_submac: IPv6 fragmentation broken (#16998)
LoRaWan node ISR stack overflowed (#14962)
lwip_sock_tcp / sock_async: received events before calling
sock_accept() are lost due to race condition. (#16303)
Missing drop implementations in netdev_driver_t::recv (#10410)
net: netdev_driver_t::send() doc unclear (#10969)
netdev_ieee802154: Mismatch between radio ll address and in memory
address (#10380)
nrf52: Not able to add global or ULA address to interface (#13280)
nrfmin: communication not possible after multicast ping with no
interval (#11405)
openthread: does not build on current Arch (#10809)
ping6 is failing when testing with cc2538dk (#13997)
pkg/tinydtls: auxiliary data API does not work for async sockets (#16054)
Possible memory leak in RIOT/build/pkg/ndn-riot/app.c (#15638)
Riot-os freezes with lwip + enc28j60 + stm32L4 (#13088)
samr30 xpro doesn't seem to use its radio ok (#12761)
scan-build errors found during 2019.07 testing (#11852)
send data with UDP at 10HZ, the program die (#11860)
stale border router does not get replaced (#12210)
tests/lwip: does not compile for IPv4 on 6LoWPAN-based boards. (#17162)
two nodes livelock sending neighbor solicitations back and forth
between each other (#16670)
Unclear how Router Solicitations are (or should be) handled (#15926)
xbee: setting PAN ID sometimes fails (#10338)

Timer related issues (15)

cpu/native: timer interrupt issue (#6442)
misc issues with tests/trickle (#9052)
MSP430: periph_timer clock config wrong (#8251)
periph/timer: timer_set() underflow safety check (tracking issue) (#13072)
periph_timer: systematic proportional error in timer_set (#10545)
saml21 system time vs rtc (#10523)
Sleep mode for Arduino (#13321)
stm32_common/periph/rtc: current implementation broken/poor accuracy (#8746)
sys/newlib: gettimeofday() returns time since boot, not current wall
time. (#9187)
tests: xtimer_drift gets stuck on native (#6052)
xtimer mis-scaling with long sleep times (#9049)
xtimer: add's items to the wrong list if the timer overflows between
_xtimer_now() and irq_disable() (#7114)
xtimer_set_msg: crash when using same message for 2 timers (#10510)
xtimer_usleep stuck for small values (#7347)
xtimer_usleep wrong delay time (#10073)

Drivers related issues (17)

(almost solved) SPI SD-Card driver: SPI initialisation freeze until
timeout (#14439)
adc is not a ADC-Driver but a analog pin abstraction (#14424)
at86rf2xx: Simultaneous use of different transceiver types is not
supported (#4876)
cpu/msp430: GPIO driver doesn't work properly (#9419)
driver/hts221: Temperature and Humidity readings incorrect (#12445)
ESP32 + DHT + SAUL reading two endpoints causes freeze. (#12057)
examples/dtls-wolfssl not working on pba-d-01-kw2x (#13527)
fail to send data to can bus (#12371)
floats and doubles being used all over the place. (#12045)
mdt_erase success, but vfs_format resets board (esp32-heltec-
lora32-v2) (#14506)
periph/spi: Switching between CPOL=0,1 problems on Kinetis with
software CS (#6567)
periph: GPIO drivers are not thread safe (#4866)
Potential security and safety race conditions on attached devices (#13444)
PWM: Single-phase initialization creates flicker (#15121)
STM32: SPI clock not returning to idle state and generating
additional clock cycles (#11104)
TCP client cannot send read only data (#16541)
Two bugs may lead to NULL dereference. (#15006)

Native related issues (6)

examples/ccn-lite: floating point exception while testing on native (#15878)
examples/micropython: floating point exception while testing on
native (#15870)
native getchar is blocking RIOT (#16834)
native not float safe (#495)
native: tlsf: early malloc will lead to a crash (#5796)
SIGFPE on native architecture when printing double floats on Ubuntu
21.04 (#16282)

Other platforms related issues (21)

Failing tests on FE310 (Hifive1b) (#13086)
[TRACKING] Fixes for automatic tests of ESP32 boards. (#12763)
arm7: printf() with float/double not working (#11885)
boards/hifive1: flashing issue (#13104)
Cannot use LLVM with Cortex-M boards (#13390)
cpu/cortexm_common: irq_enable returns the current state of
interrupts (not previous) (#10076)
cpu/sam0: flashpage write / read cycle produces different results
depending on code layout in flash (#14929)
cpu/stm32f1: CPU hangs after wake-up from STOP power mode (#13918)
esp32-wroom-32: tests/netstats_l2 failing sometimes (#14237)
esp8266 precompiled bootloaders don't support partitions past 1MB (#16402)
gcoap/esp8266: Stack overflow with gcoap example (#13606)
I found stm32 DMA periph driver bugs! when I tested stm32l431rc
board. (#16242)
Incorrect default $PORT building for esp32-wroom-32 on macOS (#10258)
MIPS: toolchain objcopy doesn't work and no .bin can be generated (#14410)
MPU doesn't work on cortex-m0+ (#14822)
newlib-nano: Printf formatting does not work properly for some
numeric types (#1891)
periph_timer: Test coverage & broken on STM32F767ZI (#15072)
riscv: ISR stack is too small for ENABLE_DEBUG in core files (#16395)
stm32152re: hardfault when DBGMCU_CR_DBG* bits are set and branch
after __WFI() (#14015)
stm32f7: Large performance difference between stm32f746 and stm32f767 (#14728)
sys/riotboot/flashwrite: unaligned write when skipping
RIOTBOOT_MAGIC on stm32wb (#15917)

Build system related issues (14)

buildtest uses wrong build directory (#9742)
make -j flash fails due to missing make dependencies or make flash-only rebuilds the .elf (#16385)
Build dependencies - processing order issues (#9913)
build: info-build doesn't work with boards without port set (#15185)
BUILD_IN_DOCKER ignores USEMODULE (#14504)
dist/tools/cppcheck/cppchck.sh: errors when running with Cppcheck
1.89 (#12771)
doxygen: riot.css modified by 'make doc' (#8122)
LTO broken (binaries too large) (#16202)
macros: RIOT_FILE_RELATIVE printing wrong file name for headers (#4053)
make: ccache leads to differing binaries (#14264)
make: Setting constants on compile time doesn't really set them
everywhere (#3256)
make: use of immediate value of variables before they have their
final value (#8913)
Tracking: remove harmful use of export in make and immediate
evaluation (#10850)
Windows AVR Mega development makefile Error (#6120)

Other issues (53)

[TRACKING] sys/shell refactoring. (#12105)
_NVIC_SystemReset stuck in infinite loop when calling pm_reboot
through shell after flashing with J-Link (#13044)
make term no longer works with JLinkExe v6.94 (#16022)
make term output is inconsistent between boards, ethos and
native (#12108)
assert: c99 static_assert macro doesn't function for multiple
static_asserts in the same scope (#9371)
Basic test for periph/rtt introduced in #15431 is incorrect (#15940)
boards/esp32-wroom-32: tests/mtd_raw flakey (#16130)
boards/saml11-xpro: second UART is broken (#17206)
Bug: openocd 0.10.0-6 Ubuntu dies while debugging with -rtos auto (#13285)
C++11 extensions in header files (#5561)
Can't build relic with benchmarks or tests (#12897)
CC2538DK board docs: broken links (#12889)
cpu/stm32/periph/rtc overflow error (#16574)
cpu/stm32: some tests are failing on CM33 (l5, u5) (#17439)
doc/LOSTANDFOUND: not rendered as expected (#17063)
edbg: long lines flooded over serial become garbled (#14548)
examples / tests: LoRa tests fail on platforms that don't support
LoRa (#14520)
File systems report names with leading slashes (#14635)
flashing issue on frdm-k64f (#15903)
frdm-k22f failing tests/periph_flashpage (#17057)
gcoap_dtls: Selecting transport at run time is not possible (#16674)
I2C not working under RIOT with U8G2 pkg (#16381)
ieee802154_security: Nonce is reused after reboot (#16844)
lwip: drivers/at86rf2xx/at86rf2xx_netdev.c invalid state during TCP
disconnect (#17209)
lwip: invalid state transition on ieee802154_submac users (#17208)
Making the newlib thread-safe (#4488)
mcuboot: flashes but no output (#17524)
nanocoap: incomplete response to /.well-known/core request (#10731)
newlib-nano: Printf formatting does not work properly with "PRIu8" (#17083)
Order of auto_init functions (#13541)
pkg/tinydtls: Multiple issues (#16108)
Possible memset optimized out in crypto code (#10751)
Potential race condition in compile_and_test_for_board.py (#12621)
pyterm on stdio_cdc_acm stops working after a few seconds (#16077)
RIOT cannot compile with the latest version of macOS (10.14) and
Xcode 10 (#10121)
RIOT is saw-toothing in energy consumption (even when idling) (#5009)
riotboot/nrf52840dk: flashing slot1 with JLINK fails (#14576)
scheduler: priority inversion problem (#7365)
sys/fmt: Missing tests for fmt_float, fmt_lpad (#7220)
sys/riotboot: documentation issues (#11243)
sys/stdio_uart: dropped data when received at once (#10639)
tests/cpp11_*: failing on i-nucleo-lrwan1 (#14578)
tests/lwip target board for python test is hardcoded to native (#6533)
tests/periph_flashpage: failing on stm32l475ve (#17280)
tests/pkg_libhydrogen: test fails on master for the samr21-xpro with
LLVM (#15066)
tests/pkg_tensorflow-lite: tests randomly failing on nrf52dk and
esp32-wroom-32 (#13133)
tests/test_tools: test fails while testing on samr21-xpro/iotlab-m3 (#15888)
tests/thread_float: crashes on avr-rss2 (#16908)
tests: broken with stdio_rtt if auto_init is disabled (#13120)
tests: some tests don't work with newlib lock functions. (#12732)
Tracker: Reduce scope on unintended COMMON variables (#2346)
usb-serial/list-ttys.sh: Broken when a debugger offers multiple
serial ports (#15814)
Use of multiple CAN bus on compatible boards (#14801)

There are 179 known issues in this release

Fixed Issues since the last release (2021.10)

sx127x: wrong RSSI values (#17451)
drivers/aip31068: initialization fails in most cases when using
esp_i2c_sw (#17311)
cpu/esp32: esp_wifi_enterprise compilation error (#17305)
ethos: race condition seems to cause packet loss (#17254)
tests/lwip_sock_ip: failing on native when using IPV4 (#17144)
Sam boards: isr_eic call all IRQ raised without taking into account
their status (enabled/disabled) (#16978)
esp8266: Hangs when erasing spi sector on mtd0 if using esp_wifi (#16281)
esp32: can't use newer C++ standard than c++11 (#15685)
tests/mpu_noexec_ram: fails on i-nucleo-lrwan1 (#14572)
Different build behavior between murdock and
riot/riotbuild:latest image (#9645)
pkg: libcoap is partially broken and outdated (#7737)

11 fixed issues since last release (2021.10)

Acknowledgements

We would like to thank all companies that provided us with hardware for porting
and testing RIOT-OS. Further thanks go to companies and institutions that
directly sponsored development time. And finally, big thanks to all of you
contributing in so many different ways to make RIOT worthwhile!

More information

http://www.riot-os.org

Matrix and Forum

Join the RIOT Matrix room at: #riot-os:matrix.org
Join the RIOT Forum at: forum.riot-os.org

License

The code developed by the RIOT community is licensed under the GNU Lesser
General Public License (LGPL) version 2.1 as published by the Free Software
Foundation.
Some external sources and packages are published under a separate license.

All code files contain licensing information.

Release-2022.01