Re: [PATCH v2 59/62] livepatch/klp-build: Introduce klp-build script for generating livepatch modules

[Josh Poimboeuf]

On Fri, Jun 06, 2025 at 04:58:35PM -0400, Joe Lawrence wrote:
> On 5/9/25 4:17 PM, Josh Poimboeuf wrote:
> > +copy_patched_objects() {
> > +	local found
> > +	local files=()
> > +	local opts=()
> > +
> > +	rm -rf "$PATCHED_DIR"
> > +	mkdir -p "$PATCHED_DIR"
> > +
> > +	# Note this doesn't work with some configs, thus the 'cmp' below.
> > +	opts=("-newer")
> > +	opts+=("$TIMESTAMP")
> > +
> > +	find_objects "${opts[@]}" | mapfile -t files
> > +
> > +	xtrace_save "processing all objects"
> > +	for _file in "${files[@]}"; do
> > +		local rel_file="${_file/.ko/.o}"
> > +		local file="$OBJ/$rel_file"
> > +		local orig_file="$ORIG_DIR/$rel_file"
> > +		local patched_file="$PATCHED_DIR/$rel_file"
> > +
> > +		[[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
> > +
> > +		cmp -s "$orig_file" "$file" && continue
> > +
> > +		mkdir -p "$(dirname "$patched_file")"
> > +		cp -f "$file" "$patched_file"
> > +		found=1
> > +	done
> > +	xtrace_restore
> > +
> > +	[[ -n "$found" ]] || die "no changes detected"
> > +
> 
> Minor nit here, I gave it a patch for files that didn't compile and
> because because files() was presumably empty:
> 
>   ./scripts/livepatch/klp-build: line 564: found: unbound variable
> 
> since found was only declared local, but never set inside the loop.

Thanks, I'm adding the following:

diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 9927d06dfdab..f689a4d143c6 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -563,7 +563,7 @@ copy_orig_objects() {
 copy_patched_objects() {
 	local files=()
 	local opts=()
-	local found
+	local found=0
 
 	rm -rf "$PATCHED_DIR"
 	mkdir -p "$PATCHED_DIR"
@@ -592,7 +592,7 @@ copy_patched_objects() {
 	done
 	xtrace_restore
 
-	[[ -n "$found" ]] || die "no changes detected"
+	(( found == 0 )) && die "no changes detected"
 
 	mv -f "$TMP_DIR/build.log" "$PATCHED_DIR"
 }