diff --git a/kernel/gen_kheaders.sh b/kernel/gen_kheaders.sh
index 473036b43..d2445af7f 100755
--- a/kernel/gen_kheaders.sh
+++ b/kernel/gen_kheaders.sh
@@ -80,11 +80,20 @@ done | cpio --quiet -pdu $cpio_dir >/dev/null 2>&1
 find $cpio_dir -type f -print0 |
 	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
 
+# The following tar invocations use options specific to GNU tar. On some
+# systems (e.g. Gentoo), `tar` can be a different tool (e.g. bsdtar), and GNU
+# tar can be found as `gtar`.
+if [ -x "$(command -v gtar)" ]; then
+	tar=gtar
+else
+	tar=tar
+fi
+
 # Create archive and try to normalize metadata for reproducibility.
 # For compatibility with older versions of tar, files are fed to tar
 # pre-sorted, as --sort=name might not be available.
 find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \
-    tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
+    $tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
     --owner=0 --group=0 --numeric-owner --no-recursion \
     -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null