On Tue, Feb 03, 2026 at 02:40:11PM -0800, Jakub Kicinski wrote:

On Tue, 3 Feb 2026 12:42:22 +0100 Thomas Weißschuh wrote:

quoted

quoted

FWIW the typelimits change broke compilation of ethtool, we'll see if
anyone "outside kernel community itself" complains.  

Can you point me to that breakage? I was unable to find it.

Not reported on the ML, and it's kinda annoying to repro because 
the uAPI header sync script isn't committed :/ You have to check 
this out

 https://git.kernel.org/pub/scm/network/ethtool/ethtool.git/

and run a script like this to sync headers from the kernel (then build):

#!/bin/bash -e

sn="${0##*/}"
export ARCH="x86_64"

if [ ! -d "$LINUX_GIT" ]; then
    echo "${sn}: LINUX_GIT not set" >&2
    exit 1
fi

pushd "$LINUX_GIT"
if [ -n "$1" ]; then
    git checkout "$1"
fi
desc=$(git describe --exact-match 2>/dev/null \
       || git show -s --abbrev=12 --pretty='commit %h')
kobj=$(mktemp -d)

make -j16 O="$kobj" allmodconfig
make -j16 O="$kobj" prepare

These are not necessary.
The UAPI generation does not need a kernel configuration.

make -j16 O="$kobj" INSTALL_HDR_PATH="${kobj}/hdr" headers_install
popd

pushd uapi
find . -type f -name '*.h' -exec cp -v "${kobj}/hdr/include/{}" {} \;

Here only those headers which already exist in ethtool's uapi/ directory
are copied. As linux/typelimits.h is new, it is now missing.
Honestly, if a user fiddles with the internals of the UAPI headers like
this, it is on them to update their code if the internal structure
changes. In your case a simple 'touch uapi/linux/typelimits.h'
before running the script will be enough. Also internal.h now requires
an explicit inclusion of <limits.h>, as that is not satisfied by the
UAPI anymore.

popd
rm -rf "$kobj"

git add uapi
git commit -s -F - <<EOT
update UAPI header copies

Update to kernel ${desc}.

EOT