Re: [mainline]Error while running make modules_install command

On Tue, 4 Nov 2025 at 18:12, Omar Sandoval osandov@osandov.com wrote:

On Tue, Nov 04, 2025 at 04:54:38PM +0530, Venkat Rao Bagalkote wrote:

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On 04/11/25 4:47 pm, Samir M wrote:

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Hello,

I am observing below error while running the make modules_install command on latest mainline kernel on IBM Power11 server.

Error: DEPMOD /lib/modules/6.18.0-rc4
depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname prefix

IBM CI has also reported this error.

Error:

depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname prefix INSTALL /boot depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname prefix depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname prefix

Git bisect is pointing to below commit as first bad commit.

d50f21091358b2b29dc06c2061106cdb0f030d03 is the first bad commit commit d50f21091358b2b29dc06c2061106cdb0f030d03 Author: Dimitri John Ledkov dimitri.ledkov@surgut.co.uk Date: Sun Oct 26 20:21:00 2025 +0000

kbuild: align modinfo section for Secureboot Authenticode EDK2 compat

Previously linker scripts would always generate vmlinuz that has

sections aligned. And thus padded (correct Authenticode calculation) and unpadded calculation would be same. As in https://github.com/rhboot/pesign userspace tool would produce the same authenticode digest for both of the following commands:

    pesign --padding --hash --in ./arch/x86_64/boot/bzImage
    pesign --nopadding --hash --in ./arch/x86_64/boot/bzImage

The commit 3e86e4d74c04 ("kbuild: keep .modinfo section in
vmlinux.unstripped") added .modinfo section of variable length.

Depending on kernel configuration it may or may not be aligned.

All userspace signing tooling correctly pads such section to calculation
spec compliant authenticode digest.

However, if bzImage is not further processed and is attempted to be

loaded directly by EDK2 firmware, it calculates unpadded Authenticode digest and fails to correct accept/reject such kernel builds even when propoer Authenticode values are enrolled in db/dbx. One can say EDK2 requires aligned/padded kernels in Secureboot.

Thus add ALIGN(8) to the .modinfo section, to esure kernels irrespective

of modinfo contents can be loaded by all existing EDK2 firmware builds.

Fixes: 3e86e4d74c04 ("kbuild: keep .modinfo section in

vmlinux.unstripped") Cc: stable@vger.kernel.org Signed-off-by: Dimitri John Ledkov dimitri.ledkov@surgut.co.uk Link: https://patch.msgid.link/20251026202100.679989-1-dimitri.ledkov@surgut.co.uk Signed-off-by: Nathan Chancellor nathan@kernel.org

include/asm-generic/vmlinux.lds.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

drgn's CI hit this same failure. FWIW, the commit fixed by this bisected commit, 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped"), also results in ELF segments of size 0 in vmlinux for some configurations, which confused drgn until I added a workaround (https://github.com/osandov/drgn/commit/2a9053de8796af866fd720a3c8c23013595d3...). So there's some funkiness in this area.

The expectation is that said section is removed from the final binary. But the fact that it is present with 0 length, indicates incorrect linking. It also now makes sense why on x86/arm it is tripping up section alignment.

As it is likely that it is the same underlying issue that such segment exists in the first place.

I wonder if the original implementation of moving sections about and when/where the builtin module info is kept is not as tidy as it was intended to be.

I wonder if we should: - rollback to the state of how things were before that feature was added - keep the production / stripped / installed kernel build as is - reshuffle of how modinfo is preserved in the unstripped kernel with a bespoke linker script

Such that hopefully we have correct alignment, without any zero length segments.

Or possibly even link / split the built-in module info somewhere else entirely.

As in revert both: - d50f21091358b (kbuild: align modinfo section for Secureboot Authenticode EDK2 compat, 2025-10-26) - 3e86e4d74c049 (kbuild: keep .modinfo section in vmlinux.unstripped, 2025-09-18)

And try implementing the keeping of .modinfo section again.

Better structure tests, after linking would be nice to catch such issues, because linker scripts are hard and trying to understand how a linker script change affects the result.