On Thu, Sep 17, 2026 at 09:52:32AM -0700, Kees Cook wrote:
> On Thu, Sep 17, 2026 at 05:06:11PM +0100, Lorenzo Stoakes (ARM) wrote:
> > -# .modinfo in vmlinux.unstripped is aligned to 8 bytes for compatibility
> > with
> > -# tools that expect vmlinux to have sufficiently aligned sections but the
> > -# additional bytes used for padding .modinfo to satisfy this requirement
> > break
> > -# certain versions of kmod with
> > -#
> > -# depmod: ERROR: kmod_builtin_iter_next: unexpected string without
> > modname prefix
> > -#
> > -# Strip the trailing padding bytes after extracting .modinfo to comply with
> > -# what kmod expects to parse.
>
> This comment still seems useful here (afaict the stripping is still
> happening with the "sed"). Maybe better to leave it, or future readers
> are left wondering what the sed is for?
Thanks for bringing this up. I think we can actually get rid of that sed
and comment altogether. It was added by
a26a6c93edfe ("kbuild: Strip trailing padding bytes from
modules.builtin.modinfo")
to fix
d50f21091358 ("kbuild: align modinfo section for Secureboot Authenticode EDK2
compat")
but I do not think that this alignment is needed anymore since I
properly fixed Dimitri's issue in
8678591b4746 ("kbuild: Split .modinfo out from ELF_DETAILS")
So I think we could go with something like
>From 008046b33ef4b476048e3ddb2c679a453254e535 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <[email protected]>
Date: Thu, 17 Sep 2026 17:29:53 -0700
Subject: [PATCH] kbuild: Remove alignment on .modinfo section
Commit d50f21091358 ("kbuild: align modinfo section for Secureboot
Authenticode EDK2 compat") aligned .modinfo because it appeared in the
x86_64 compressed kernel image after commit 3e86e4d74c04 ("kbuild: keep
.modinfo section in vmlinux.unstripped"), breaking boot.
Commit 8678591b4746 ("kbuild: Split .modinfo out from ELF_DETAILS")
properly addresses .modinfo appearing in unexpected contexts like
compressed images by moving it out of ELF_DETAILS and explicitly
specifying its location in every architecture's vmlinux linker script or
discarding it where it may appear elsewhere.
Effectively revert commit d50f21091358 ("kbuild: align modinfo section
for Secureboot Authenticode EDK2 compat") and its follow up fix,
commit a26a6c93edfe ("kbuild: Strip trailing padding bytes from
modules.builtin.modinfo"), as they are no longer necessary in the
current tree. This simplifies future cleanups.
Signed-off-by: Nathan Chancellor <[email protected]>
---
include/asm-generic/vmlinux.lds.h | 2 +-
scripts/Makefile.vmlinux | 10 ----------
2 files changed, 1 insertion(+), 11 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h
b/include/asm-generic/vmlinux.lds.h
index b2988aa12f66..26201821ea7f 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -855,7 +855,7 @@
KLP_SYMID
#define MODINFO
\
- .modinfo : { *(.modinfo) . = ALIGN(8); }
+ .modinfo : { *(.modinfo) }
#ifdef CONFIG_GENERIC_BUG
#define BUG_TABLE \
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index fcae1e432d9a..6833b517cacb 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -102,18 +102,8 @@ vmlinux: vmlinux.unstripped FORCE
# modules.builtin.modinfo
# ---------------------------------------------------------------------------
-# .modinfo in vmlinux.unstripped is aligned to 8 bytes for compatibility with
-# tools that expect vmlinux to have sufficiently aligned sections but the
-# additional bytes used for padding .modinfo to satisfy this requirement break
-# certain versions of kmod with
-#
-# depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname
prefix
-#
-# Strip the trailing padding bytes after extracting .modinfo to comply with
-# what kmod expects to parse.
quiet_cmd_modules_builtin_modinfo = GEN $@
cmd_modules_builtin_modinfo = $(cmd_objcopy); \
- sed -i 's/\x00\+$$/\x00/g' $@; \
chmod -x $@
OBJCOPYFLAGS_modules.builtin.modinfo := -j .modinfo -O binary
--
Then this patch becomes much more obvious (at least to me)
diff --git a/include/asm-generic/vmlinux.lds.h
b/include/asm-generic/vmlinux.lds.h
index 26201821ea7f..a6730d34e8c6 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -855,7 +855,7 @@
KLP_SYMID
#define MODINFO
\
- .modinfo : { *(.modinfo) }
+ .modinfo (INFO) : { *(.modinfo) }
#ifdef CONFIG_GENERIC_BUG
#define BUG_TABLE \
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index 6833b517cacb..95b523fe4f9e 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -89,11 +89,8 @@ remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) +=
'.rel.*'
remove-symbols := -w --strip-unneeded-symbol='__mod_device_table__*'
-# To avoid warnings: "empty loadable segment detected at ..." from GNU objcopy,
-# it is necessary to remove the PT_LOAD flag from the segment.
quiet_cmd_strip_relocs = OBJCOPY $@
- cmd_strip_relocs = $(OBJCOPY) $(patsubst %,--set-section-flags
%=noload,$(remove-section-y)) $< $@; \
- $(OBJCOPY) $(addprefix
--remove-section=,$(remove-section-y)) $(remove-symbols) $@
+ cmd_strip_relocs = $(OBJCOPY) $(addprefix
--remove-section=,$(remove-section-y)) $(remove-symbols) $< $@
targets += vmlinux
vmlinux: vmlinux.unstripped FORCE
@@ -103,10 +100,7 @@ vmlinux: vmlinux.unstripped FORCE
# ---------------------------------------------------------------------------
quiet_cmd_modules_builtin_modinfo = GEN $@
- cmd_modules_builtin_modinfo = $(cmd_objcopy); \
- chmod -x $@
-
-OBJCOPYFLAGS_modules.builtin.modinfo := -j .modinfo -O binary
+ cmd_modules_builtin_modinfo = $(OBJCOPY) -O binary -j .modinfo
--dump-section .modinfo=$@ $< /dev/null
targets += modules.builtin.modinfo
modules.builtin.modinfo: vmlinux.unstripped FORCE
--
Thoughts?
--
Cheers,
Nathan
