On Fri, Jul 14, 2023 at 04:30:02PM +0200, Michal Such�nek wrote:

Hello,

On Fri, Jul 14, 2023 at 04:05:10PM +0200, Nicolas Schier wrote:

quoted

On Fri, Jul 14, 2023 at 02:21:08PM +0200 Michal Suchanek wrote:

quoted

Some distributions aim at not shipping any files in / outside of usr.

For me, preventing negation often makes things easier, e.g.: "... aim at
shipping files only below /usr".

quoted

The path under which kernel modules are installed is hardcoded to /lib
which conflicts with this goal.

When kmod provides the config command, use it to determine the correct
module installation prefix.

This is a prefix under which the modules are searched by kmod on the
system, and is separate from the temporary staging location already
supported by INSTALL_MOD_PATH.

With kmod that does not provide the config command empty prefix is used
as before.

Signed-off-by: Michal Suchanek <redacted>
---
v2: Avoid error on systems with kmod that does not support config
command
v3: More verbose commit message
---
 Makefile          | 4 +++-
 scripts/depmod.sh | 8 ++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 47690c28456a..b1fea135bdec 100644
--- a/Makefile
+++ b/Makefile

@@ -1165,7 +1165,9 @@ export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
 # makefile but the argument can be passed to make if needed.
 #
 
-MODLIB	= $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
+export KERNEL_MODULE_PREFIX := $(shell kmod config &> /dev/null && kmod config | jq -r .module_prefix)

All other calls of `jq` that I could find are located at tools/; as this here
is evaluated on each invocation, this should probably be documented in
Documentation/process/changes.rst?

(Absence of `jq` will cause error messages, even with CONFIG_MODULES=n.)

That's a good point.

quoted

quoted

+
+MODLIB	= $(INSTALL_MOD_PATH)$(KERNEL_MODULE_PREFIX)/lib/modules/$(KERNELRELEASE)
 export MODLIB
 
 PHONY += prepare0

diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index 3643b4f896ed..88ac79056153 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh

@@ -27,16 +27,16 @@ fi
 # numbers, so we cheat with a symlink here
 depmod_hack_needed=true
 tmp_dir=$(mktemp -d ${TMPDIR:-/tmp}/depmod.XXXXXX)
-mkdir -p "$tmp_dir/lib/modules/$KERNELRELEASE"
+mkdir -p "$tmp_dir$KERNEL_MODULE_PREFIX/lib/modules/$KERNELRELEASE"
 if "$DEPMOD" -b "$tmp_dir" $KERNELRELEASE 2>/dev/null; then
-	if test -e "$tmp_dir/lib/modules/$KERNELRELEASE/modules.dep" -o \
-		-e "$tmp_dir/lib/modules/$KERNELRELEASE/modules.dep.bin"; then
+	if test -e "$tmp_dir$KERNEL_MODULE_PREFIX/lib/modules/$KERNELRELEASE/modules.dep" -o \
+		-e "$tmp_dir$KERNEL_MODULE_PREFIX/lib/modules/$KERNELRELEASE/modules.dep.bin"; then
 		depmod_hack_needed=false
 	fi
 fi

I'd like to come back to the statement from Masahiro: Is the check above,
against some very old versions of depmod [1], the only reason for this patch?  

If we could remove that, would

    make INSTALL_MOD_PATH="$(kmod config | jq -r .module_prefix)" modules_install

be sufficient?

No, the INSTALL_MOD_PATH is passed as the -b argument to depmod while
the newly added part is not because it's integral part of where the
modules are installed on the system, and not the staging area path.

Ah, thanks.  So just for my understanding, could this be a (non-gentle)
alternative version of your patch, w/o modifying top-level Makefile?

diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index 3643b4f896ed..72c819de0669 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # SPDX-License-Identifier: GPL-2.0
 #
 # A depmod wrapper used by the toplevel Makefile

@@ -23,6 +23,8 @@ if [ -z $(command -v $DEPMOD) ]; then
        exit 0
 fi
 
+kmod_version=$(( $(kmod --version | sed -rne 's/^kmod version ([0-9]+).*$/\1/p') ))
+
 # older versions of depmod require the version string to start with three
 # numbers, so we cheat with a symlink here
 depmod_hack_needed=true

@@ -35,6 +37,13 @@ if "$DEPMOD" -b "$tmp_dir" $KERNELRELEASE 2>/dev/null; then
        fi
 fi
 rm -rf "$tmp_dir"
+
+if [ "${kmod_version}" -gt 32 ]; then
+       kmod_prefix="$(kmod config | jq -r .module_prefix)"
+       INSTALL_MOD_PATH="${INSTALL_MOD_PATH#${kmod_prefix}"
+       depmod_hack_needed=false
+fi
+
 if $depmod_hack_needed; then
        symlink="$INSTALL_MOD_PATH/lib/modules/99.98.$KERNELRELEASE"
        ln -s "$KERNELRELEASE" "$symlink"

(untested, and assuming that kmod module prefix is in kmod >= 32)

Or are I am still missing something?

Was busybox ever fixed to not require the hack?

I haven't checked that, yet.

Kind regards,
Nicolas