On Thu, Feb 05, 2026 at 11:35:00AM -0500, Joe Lawrence wrote:
> On Wed, Feb 04, 2026 at 10:02:38AM -0800, Josh Poimboeuf wrote:
> > On Tue, Feb 03, 2026 at 09:51:37PM -0500, Joe Lawrence wrote:
> > > The klp-build script prepares a clean patch by populating two temporary
> > > directories ('a' and 'b') with source files and diffing the result.
> > > However, this process currently fails when a patch introduces a new
> > > source file as the script attempts to copy files that do not yet exist
> > > in the original source tree. Likewise, there is a similar limitation
> > > when a patch removes a source file and the script tries to copy files
> > > that no longer exist.
> > >
> > > Refactor the file-gathering logic to distinguish between original input
> > > files and patched output files:
> > >
> > > - Split get_patch_files() into get_patch_input_files() and
> > > get_patch_output_files() to identify which files exist before and
> > > after patch application.
> > > - Filter out "/dev/null" from both to handle file creation/deletion
> > > - Update refresh_patch() to only copy existing input files to the 'a'
> > > directory and the resulting output files to the 'b' directory.
> > >
> > > This allows klp-build to successfully process patches that add or remove
> > > source files.
> > >
> > > Signed-off-by: Joe Lawrence <[email protected]>
> > > ---
> > > scripts/livepatch/klp-build | 34 +++++++++++++++++++++++++++-------
> > > 1 file changed, 27 insertions(+), 7 deletions(-)
> > >
> > > Lightly tested with patches that added or removed a source file, as
> > > generated by `git diff`, `git format-patch`, and `diff -Nupr`.
> > >
> > > diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
> > > index 9f1b77c2b2b7..5a99ff4c4729 100755
> > > --- a/scripts/livepatch/klp-build
> > > +++ b/scripts/livepatch/klp-build
> > > @@ -299,15 +299,33 @@ set_kernelversion() {
> > > sed -i "2i echo $localversion; exit 0" scripts/setlocalversion
> > > }
> > >
> > > -get_patch_files() {
> > > +get_patch_input_files() {
> > > + local patch="$1"
> > > +
> > > + grep0 -E '^--- ' "$patch" \
> > > + | gawk '{print $2}' \
> > > + | grep -v '^/dev/null$' \
> >
> > Because pipefail is enabled, the grep0 helper should be used instead of
> > grep, otherwise a failed match can propagate to an error. Maybe we need
> > a "make check" or something which enforces that and runs shellcheck.
> >
>
> Good catch. So your idea is to drop a Makefile in scripts/livepatch
> with a check target that runs shellcheck and then a klp-build specific
> check for any non-grep0 grep? (like `grep -w 'grep' klp-build`). If
> so, any other things to should check for?
That's all I can think of, hopefully shellcheck would catch most of the
other footguns.
--
Josh
