kpatch-build: fix Fedora 42+ kernel source directory nesting

kpatch-build/kpatch-build

@@ -39,6 +39,7 @@ set -o pipefail
 
 BASE="$PWD"
 SCRIPTDIR="$(readlink -f "$(dirname "$(type -p "$0")")")"
+source "$SCRIPTDIR/kpatch-funcs.sh"
 ARCH="$(uname -m)"
 TARGET_ARCH="${TARGET_ARCH:-$ARCH}"
 CPUS="$(getconf _NPROCESSORS_ONLN)"
@@ -1082,7 +1083,7 @@ else
 		elif [[ "$DISTRO" = photon ]]; then
 			mv "$RPMTOPDIR"/BUILD/linux-"$KVER" "$KERNEL_SRCDIR" 2>&1 | logger || die
 		else
-			mv "$RPMTOPDIR"/BUILD/kernel-*/linux-* "$KERNEL_SRCDIR" 2>&1 | logger || die
+			find_rpm_linux_srcdir
 		fi
 
 		rm -rf "$RPMTOPDIR"

kpatch-build/kpatch-funcs.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+#
+# Shared helper functions for kpatch-build (and tests).
+#
+# Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
+# Copyright (C) 2013,2014 Josh Poimboeuf <jpoimboe@redhat.com>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA,
+# 02110-1301, USA.
+
+# Find and move the linux source directory from an RPM BUILD tree.
+# Handles both traditional flat layout (Fedora < 42, RHEL, CentOS):
+#   BUILD/kernel-6.12.0/linux-6.12.0-100.fc41.x86_64/
+# and nested layout (Fedora 42+):
+#   BUILD/kernel-6.14.0-build/kernel-6.14/linux-6.14.0-63.fc42.x86_64/
+#
+# Uses: RPMTOPDIR, KERNEL_SRCDIR (must be set by caller)
+find_rpm_linux_srcdir() {
+	shopt -s nullglob
+	local dirs=( "$RPMTOPDIR"/BUILD/kernel-*/linux-* )
+	shopt -u nullglob
+
+	if [[ ${#dirs[@]} -eq 1 ]]; then
+		mv "${dirs[0]}" "$KERNEL_SRCDIR" 2>&1 | logger || die
+	elif [[ ${#dirs[@]} -gt 1 ]]; then
+		die "Multiple linux-* directories found in BUILD: ${dirs[*]}"
+	else
+		local found
+		found=$(find "$RPMTOPDIR/BUILD" -maxdepth 3 -type d -name "linux-*" \
+			! -path "*/configs/*")
+		if [[ -z "$found" ]]; then
+			die "Could not find linux source directory under $RPMTOPDIR/BUILD"
+		elif [[ $(echo "$found" | wc -l) -gt 1 ]]; then
+			die "Multiple linux source directories under $RPMTOPDIR/BUILD: $found"
+		else
+			mv "$found" "$KERNEL_SRCDIR" 2>&1 | logger || die
+		fi
+	fi
+}

test/unit/test-fedora-source-nesting.sh

@@ -0,0 +1,69 @@
+#!/bin/bash
+# Test find_rpm_linux_srcdir() from kpatch-build.
+#
+# Verifies source directory detection across RPM BUILD layouts:
+#   Flat:   BUILD/kernel-6.12.0/linux-6.12.0-100.fc41.x86_64/         (Fedora <42, RHEL, CentOS)
+#   Nested: BUILD/kernel-6.14.0-build/kernel-6.14/linux-6.14.0-63.fc42.x86_64/  (Fedora 42+)
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")/../.." && pwd)"
+
+# Stub kpatch-build helpers so die doesn't exit and logger doesn't need a logfile.
+die()    { echo "die: $*" >&2; return 1; }
+logger() { cat >/dev/null; }
+
+source "$SCRIPT_DIR/kpatch-build/kpatch-funcs.sh"
+
+TESTDIR=$(mktemp -d)
+trap 'rm -rf "$TESTDIR"' EXIT
+ERRORS=0
+
+# Create a BUILD tree, run find_rpm_linux_srcdir, check result.
+#   $1 = test name
+#   $2 = expected: "ok" (source moved) or "fail" (die called)
+#   $3... = paths to create under BUILD/
+assert_layout() {
+	local name="$1" expect="$2"; shift 2
+	local dir="$TESTDIR/$name"
+	local rc=0
+
+	mkdir -p "$dir/BUILD" "$dir/dest"
+	for p in "$@"; do mkdir -p "$dir/BUILD/$p"; done
+
+	RPMTOPDIR="$dir" KERNEL_SRCDIR="$dir/dest/linux" \
+		find_rpm_linux_srcdir 2>/dev/null || rc=$?
+
+	case "$expect" in
+		ok)   [[ $rc -eq 0 && -d "$dir/dest/linux" ]] || { echo "FAIL  $name"; ((ERRORS++)); return; } ;;
+		fail) [[ $rc -ne 0 ]] || { echo "FAIL  $name — expected error"; ((ERRORS++)); return; } ;;
+	esac
+	echo "ok    $name"
+}
+
+# Flat layout: Fedora 41 / RHEL / CentOS
+assert_layout "flat-fc41-x86_64"   ok    "kernel-6.12.0/linux-6.12.0-100.fc41.x86_64"
+assert_layout "flat-fc41-aarch64"  ok    "kernel-6.12.0/linux-6.12.0-100.fc41.aarch64"
+assert_layout "flat-rhel9"         ok    "kernel-5.14.0/linux-5.14.0-362.el9.x86_64"
+
+# Nested layout: Fedora 42+
+assert_layout "nested-fc42"        ok    "kernel-6.14.0-build/kernel-6.14/linux-6.14.0-63.fc42.x86_64"
+assert_layout "nested-fc42-arm"    ok    "kernel-6.14.0-build/kernel-6.14/linux-6.14.0-63.fc42.aarch64"
+
+# configs/linux-* dirs must be ignored by the nested search
+assert_layout "nested-with-configs" ok   "kernel-6.14.0-build/configs/linux-extra" \
+                                         "kernel-6.14.0-build/kernel-6.14/linux-6.14.0-63.fc42.x86_64"
+
+# Error: ambiguous (multiple matches)
+assert_layout "multi-flat"         fail  "kernel-6.14.0/linux-6.14.0-aaa" \
+                                         "kernel-6.14.0/linux-6.14.0-bbb"
+assert_layout "multi-nested"       fail  "kernel-6.14.0-build/kernel-6.14/linux-aaa" \
+                                         "kernel-6.14.0-build/kernel-6.14/linux-bbb"
+
+# Error: nothing to find
+assert_layout "empty-build"        fail
+assert_layout "no-linux-dir"       fail  "kernel-6.14.0-build/kernel-6.14/sources"
+assert_layout "too-deep"           fail  "a/b/c/d/linux-6.14.0"
+
+echo ""
+[[ $ERRORS -gt 0 ]] && { echo "$ERRORS test(s) failed"; exit 1; }
+echo "All tests passed."