Development statistics for 6.17

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Work on 6.17 was contributed by 2,038 developers, of whom 298 made their first kernel contribution during this cycle. The most active contributors this time around were:

Most active 6.17 developers

By changesets Bartosz Golaszewski 207 1.6% Sean Christopherson 168 1.3% Takashi Iwai 162 1.2% Al Viro 141 1.1% Krzysztof Kozlowski 138 1.1% Jakub Kicinski 135 1.0% Eric Biggers 127 1.0% Ian Rogers 121 0.9% Rob Herring 104 0.8% David Lechner 92 0.7% Filipe Manana 90 0.7% Anusha Srivatsa 90 0.7% Jani Nikula 88 0.7% SeongJae Park 87 0.7% Masahiro Yamada 86 0.7% Matthew Wilcox 84 0.6% Alex Deucher 83 0.6% Dmitry Baryshkov 83 0.6% Lad Prabhakar 82 0.6% Binbin Zhou 79 0.6%

By changed lines Dennis Dalessandro 48357 7.8% Takashi Iwai 20562 3.3% Bingbu Cao 16171 2.6% Luca Weiss 12815 2.1% Eric Biggers 12775 2.1% Rob Clark 8666 1.4% Rob Herring 8095 1.3% Ian Rogers 7008 1.1% Liu Ying 6803 1.1% Jakub Kicinski 6489 1.0% Jani Nikula 5739 0.9% Ivan Vecera 5261 0.8% Lorenzo Pieralisi 5158 0.8% Svyatoslav Ryhel 5115 0.8% Frank Li 5074 0.8% Dmitry Baryshkov 4724 0.8% Sean Christopherson 4554 0.7% Andrea della Porta 4531 0.7% Cathy Xu 4378 0.7% Thomas Zimmermann 4240 0.7%

The top contributor of changesets this time around was Bartosz Golaszewski, who carried out some extensive refactoring in the GPIO and pin-control driver subsystems. Sean Christopherson, as always, was busy throughout the KVM subsystem. Takashi Iwai, beyond maintaining the sound subsystem, eliminated large numbers of strcpy() calls there. Al Viro made extensive changes in the virtual filesystem layer (and beyond), and Krzysztof Kozlowski worked mostly with devicetree bindings and system-on-chip drivers.

Dennis Dalessandro only contributed two commits to 6.17, but the one removing the old "qib" Infiniband driver put him at the top of the "lines changed" column. Takashi Iwai reorganized some codec drivers. Bingbu Cao added the IPU7 input system driver to the staging tree, Luca Weiss added a number of drivers for the Milos system-on-chip, and Eric Biggers added a set of tests for cryptographic functions.

In this cycle, 8.1% of the commits carried Tested-by tags, while 53.6% had Reviewed-by tags. The top testers and reviewers for 6.17 were:

Test and review credits in 6.17
Tested-by Daniel Wheeler 96 7.8% Randy Dunlap 46 3.8% Rinitha S 45 3.7% Antonino Maniscalco 42 3.4% Tomi Valkeinen 34 2.8% Neil Armstrong 29 8.7% Vikash Garodia 26 2.1% K Prateek Nayak 26 2.1% Sairaj Kodilkar 23 1.9% Hiago De Franco 21 1.7%	Reviewed-by Simon Horman 237 2.5% Dmitry Baryshkov 180 1.9% Geert Uytterhoeven 154 1.6% Neil Armstrong 147 1.6% Andy Shevchenko 142 1.5% Krzysztof Kozlowski 140 1.5% David Sterba 122 1.3% Ilpo Järvinen 122 1.3% Laurent Pinchart 117 1.3% Andrew Lunn 107 1.1%

Daniel Wheeler remains unapproachable as the top tester of commits going into the kernel. On the review side, Simon Horman managed to review nearly four patches for each day of this development cycle; 31 developers reviewed at least one patch per day during this time.

Employer information

There were 209 employers identified as having supported work on the 6.17 kernel; the most active of those were:

Most active 6.17 employers

By changesets Intel 1313 10.0% (Unknown) 1118 8.5% Google 1102 8.4% Red Hat 953 7.3% Linaro 679 5.2% SUSE 612 4.7% Meta 517 3.9% AMD 515 3.9% Qualcomm 420 3.2% NVIDIA 416 3.2% (None) 408 3.1% Renesas Electronics 332 2.5% Oracle 293 2.2% Huawei Technologies 273 2.1% Arm 265 2.0% NXP Semiconductors 225 1.7% Linutronix 192 1.5% IBM 176 1.3% (Consultant) 172 1.3% BayLibre 151 1.2%

By lines changed Intel 69817 11.3% Cornelis Networks 48357 7.8% Google 47540 7.7% (Unknown) 45034 7.3% SUSE 36005 5.8% Red Hat 30886 5.0% Qualcomm 29443 4.8% Meta 23930 3.9% NVIDIA 22106 3.6% Linaro 18498 3.0% AMD 16085 2.6% NXP Semiconductors 15617 2.5% (None) 13361 2.2% Renesas Electronics 13205 2.1% Fairphone 12815 2.1% Arm 12577 2.0% Huawei Technologies 10675 1.7% IBM 10577 1.7% Analog Devices 9147 1.5% Microsoft 6865 1.1%

These results change little from one release to the next. Cornelis Networks is an unusual name to see here, though; sharp-eyed readers will notice that the number of lines changed is exactly equal to that of Dennis Dalessandro, who was mentioned above.

Bugs introduced and fixed

When kernel developers fix a bug, they normally include a Fixes tag that identifies the commit in which the bug was introduced. Among other things, that allows for various types of interesting analysis, including for bug lifetime and such. The 6.17 kernel, for example, fixes 245 bugs that were introduced in 6.16, but also two that have been present since the beginning of the Git era in 2005 (subscribers can consult this KSDB page for lots of details on where the bugs fixed in 6.17 came from).

One specific question that one might attempt to answer with this data is: are kernel developers fixing more bugs than they introduce (thus reducing total bugs) or not? We asked that question nearly three years ago, with a result that looked like this:

At that time, the plot appeared to show that, as of the 5.0 release, the number of bugs fixed exceeded the number introduced, but that result was never expected to match reality. As has often been shown, it takes a long time to find all of the bugs introduced in a release; in 2022, there had not been enough time to find all of the bugs that showed up in 5.0 (released in 2019).

Running the same analysis now produces this plot:

As one might expect, the 5.0 kernel is now shown to have introduced more bugs than it fixed; the apparent crossover point has moved to 5.8. With enough handwaving, one can come up with all kinds of conclusions from this shift. For example, there were 16 kernel releases made between those two plots, but the crossover point only moved by eight, suggesting that it is taking longer to find the requisite number of bugs in any given kernel release, despite the observable fact that we are fixing more bugs in each release over time. If that reasoning holds, there may eventually come a point where we can say with confidence that a given release has fixed more bugs than it introduced.

Another question one can ask is: which commits have required the most fixes over time — which were the buggiest commits ever made to the kernel? As of 6.17, the answer to that question is:

Commit	Fixes	Description
1da177e4c3f4	657	Linux-2.6.12-rc2
dd08ebf6c352	159	drm/xe: Introduce a new DRM driver for Intel GPUs
8700e3e7c485	79	Soft RoCE driver
e126ba97dba9	75	mlx5: Add driver for Mellanox Connect-IB adapters
9d71dd0c7009	58	can: add support of SAE J1939 protocol
46a3df9f9718	54	net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support
604326b41a6f	51	bpf, sockmap: convert to generic sk_msg interface
d889913205cf	48	wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices
98686cd21624	46	wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices
d5c65159f289	46	ath11k: driver for Qualcomm IEEE 802.11ax devices
e7096c131e51	46	net: WireGuard secure network tunnel
1738cd3ed342	44	net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)
76ad4f0ee747	41	net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC
e1eaea46bb40	39	tty: n_gsm line discipline
1e51764a3c2a	38	UBIFS: add new flash file system
1ac5a4047975	37	RDMA/bnxt_re: Add bnxt_re RoCE driver
1c1008c793fa	35	net: bcmgenet: add main driver file
7733f6c32e36	34	usb: cdns3: Add Cadence USB3 DRD Driver
25fdd5933e4c	33	drm/msm: Add SDM845 DPU support
54a611b60590	33	Maple Tree: add new data structure
3d82904559f4	33	usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver
b48c24c2d710	32	RDMA/irdma: Implement device supported verb APIs
c09440f7dcb3	31	macsec: introduce IEEE 802.1AE driver
c0c050c58d84	31	bnxt_en: New Broadcom ethernet driver.
7724105686e7	29	IB/hfi1: add driver files
4c8ff7095bef	29	f2fs: support data compression
6a98d71daea1	28	RDMA/rtrs: client: main functionality
96518518cc41	27	netfilter: add nftables
3f518509dedc	26	ethernet: Add new driver for Marvell Armada 375 network unit
c948b5da6bbe	26	wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips
e2f34481b24d	26	cifsd: add server-side procedures for SMB3
3c4d7559159b	26	tls: kernel TLS support
a49d25364dfb	26	staging/atomisp: Add support for the Intel IPU v2
d2ead1f360e8	25	net/mlx5e: Add kTLS TX HW offload support
726b85487067	25	qla2xxx: Add framework for async fabric discovery
119f5173628a	25	drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.
152d1faf1e2f	25	arm64: dts: qcom: add SC8280XP platform
c156633f1353	25	Renesas Ethernet AVB driver proper
44e694958b95	24	drm/xe/display: Implement display support
a05829a7222e	24	cfg80211: avoid holding the RTNL when calling the driver

Commit 1da177e4c3f4 is the original commit that started the Git era, so any bugs seemingly introduced there could have come anytime in the first 14 years of the kernel's development history. As Andrew Morton recently observed: "we really blew it that time!". Perhaps most notable is the second-place commit, adding the xe graphics driver, which only landed in the kernel for the 6.8 release and has quickly accumulated Fixes tags. Beyond that, it remains true that many of the most-fixed commits in the kernel history come from the networking subsystem, for reasons that are far from clear.

As of this writing, there are just over 11,300 non-merge commits waiting in linux-next, which has not been updated for a few days. Those commits will soon spill into the mainline for the 6.18 release, starting the whole process over yet again. As always, LWN will be there keeping an eye on that release as it comes into shape; stay tuned.