Large test patches inflate the selftest share of Linux 7.3-rc5's diffstat
Linus Torvalds said selftests make up a quarter of the Linux 7.3-rc5 patch by line count, a split he called unusual. A few very large test patches produce that share, so the size of the rc alone gives teams planning for 7.3 little reason to wait.
The Engineer · Build desk
What happened
- Torvalds wrote that the single biggest patch in rc5 is, he thinks, the arm64 KVM ITS table test.
- Most of the rc5 driver changes were networking, with DRM graphics drivers a close second.
- The rc5 merges include more Cache Aware Scheduling fixes, support for new mice and other HID devices, and a revert of Logitech Holt Receiver HID++ support over issues.
- Linux 7.3 is due for release in October and will power Ubuntu 26.10 and other autumn distributions.
Why it matters
- What doesn't add up contradiction Phoronix ties the kernel's busy pace to AI agents while Torvalds sees no pattern beyond size, so the selftest quarter cannot be read as a tally of agent-found bugs in rc5.
- Who has to decide decision Teams qualifying 7.3 should weight testing toward KVM, scheduler and BPF paths, where most of rc5's change outside drivers and tests landed.
- What it costs cost Anyone who validated Logitech receivers against HID++ support in an earlier 7.3 candidate has to retest on rc5, because that support has been reverted.
- Who's exposed exposure Ubuntu 26.10 users inherit whatever the remaining 7.3 candidates fix, or miss, in the KVM and scheduler code still being patched.
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Ubuntu 26.10 ships a near-final Linux 7.3 and finishes the Rust coreutils switchConfirmed2 publishers
Torvalds called the selftest figure "admittedly a bit misleading" in the same paragraph that reported it [4]. The quarter is a share of the diffstat, the summary that weighs each patch by how many lines it changes [3]. He explained that "most of the driver patches are rather small, and some of the selftest patches are much bigger" [4]. A handful of big test patches can hold a large share of the lines without making up a large share of the commits [4][6]. Counting commits, he wrote, "it skews quite differently" [6].
The line shares still show where the code outside the tests sits. Drivers were under a third of the diff [3]. Add the selftest quarter, and more than 40 percent is left for everything else [12]. Torvalds put most of that remainder in architecture fixes, "largely kvm-related, some perf", and "a fair amount of core kernel (both scheduler and bpf)" [7]. Networking, core VFS and some XFS fixes make up the rest [7].
According to Phoronix, kernel development is as busy as ever, "driven in large part by AI/LLM agents continuing to uncover new issues" in a codebase of nearly 41 million lines [13]. The attribution is Phoronix's own, and it covers kernel development in general [13]. The announcement text Phoronix published does not mention AI agents [14]. Torvalds explained the size more briefly: "I don't think there's any real pattern to it other than 'big'." [1]
On a fleet without KVM hosts, rc5 is an even weaker case for extra soak time. The architecture fixes Torvalds listed are largely KVM-related [7]. His rating of the diffstat was "Not *bad* unusual, just not what I typically see." [10] He added that "nothing looks particularly alarming" and ended with "Please keep testing" [1][2].
What to watch
- The rc6 and rc7 announcements: whether Torvalds again calls the release large, and whether the selftest share drops once the big KVM test patches are in.
- Whether Logitech Holt Receiver HID++ support returns before the October release or moves to a later kernel.
- Further Cache Aware Scheduling fixes in rc6 or later, a sign the scheduler work is still settling.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence78
- Adoption
- Not scored
- Hype gap+5
- Incentives
- Not scored
- Confidence72
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
I don't think there's any real pattern to it other than 'big'. But nothing looks particularly alarming, I think that despite the diffstat it's just the same old, same old.
- [2]
Please keep testing
- [3]
In the Linux 7.3-rc5 announcement, Linus Torvalds wrote: "The diffstat looks a bit unusual. Less than a third of the patch is drivers, and a quarter is just selftests."
- [4]
Now, that's admittedly a bit misleading: most of the driver patches are rather small, and some of the selftest patches are much bigger
- [5]
Torvalds wrote that the biggest patch in 7.3-rc5 is, he thinks, the arm64 KVM ITS table test.
- [6]
So counting the number of commits it skews quite differently.
- [7]
Torvalds wrote that the rest of rc5 is mostly architecture fixes (largely kvm-related, some perf) and a fair amount of core kernel (both scheduler and bpf), plus networking, with various scattered fixes in core vfs and some xfs.
- [8]
Torvalds wrote that most of the driver side of rc5 is networking, with drm showing up as a close second.
- [9]
Linux 7.3-rc5 merged more Cache Aware Scheduling fixes, support for some new mice and other HID devices, a revert of Logitech Holt Receiver HID++ support due to issues, and numerous graphics driver fixes.
- [10]
Not *bad* unusual, just not what I typically see.
- [11]
Linux 7.3 will power Ubuntu 26.10 and other autumn Linux distributions upon its October release.
- [12]
More than 40 percent of the 7.3-rc5 diff by lines is outside drivers and selftests.
- [13]
Phoronix wrote that Linux kernel development continues to be as busy as ever, driven in large part by AI/LLM agents continuing to uncover new issues in the nearly 41 million line codebase.
- [14]
The full Torvalds rc5 announcement text as published by Phoronix does not mention AI or LLM agents.
Sources
2 independent publishers whose own reporting we read for this story.
- lwn.netKernel prepatch 7.3-rc5
1 article · September 27, 2026
- phoronix.comLinux 7.3-rc5 Released: "Another Week, Another Large RC"
1 article · September 27, 2026
Topics and entities
Topics
- Linux Kernel Releases