LWN: Comments on "Development statistics for 6.17"

Fixes tags in networking

error27 — Wed, 01 Oct 2025 12:20:59 +0000

I haven't done the numbers but I know that these things are true and obviously are going to affect the numbers. The networking subsystem was started enforcing that people must add a Fixes tag before other subsystems did. The second thing is that in the last few years a lot subsystems have started rebasing more. So if you fix a commit in linux-next, these days a lot of subsystems will fold the fix into the original commit instead of applying it as a separate patch. Networking doesn't rebase.

Also networking is quite big and active.

Bugs per commit

npws — Tue, 30 Sep 2025 16:29:04 +0000

It seems to derive any conclusions from the bug numbers, they at least need to be put in relation to the LOC of the commit that introduced them, or some related metric. It is hardly a surprise that 10000 lines of code contain more bugs then 10 lines of code.

Bugs per commit

iabervon — Tue, 30 Sep 2025 14:43:31 +0000

It looks like the commits that introduce the most bugs are mostly the ones that add new drivers, which makes sense in that they also introduce more new code, in general, and also generally don't have any tests for corner cases the author didn't think of (unlike changes that often have tests that someone wrote previously). And they generally can't cause regressions (other than hardware users didn't need waking up and causing problems), so the bugs take longer to notice.

You could reasonably say that the addition of the xe driver broke down the single big bug (of the hardware being entirely unsupported) into a lot of smaller, harder-to-trigger bugs and fixed a lot of test cases while leaving a relatively small number of test cases unaddressed.

"many of the most-fixed commits in the kernel history come from the networking subsystem"

alison — Tue, 30 Sep 2025 04:35:38 +0000

Plausible explanations might be that networking subsystem bugs are easier to discover, or that the networking subsystem tends to merge larger single commits than other subsystems.