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authorNathan Chancellor <nathan@kernel.org>2025-11-05 15:30:27 -0700
committerNathan Chancellor <nathan@kernel.org>2025-11-06 09:50:23 -0700
commita26a6c93edfeee82cb73f55e87d995eea59ddfe8 (patch)
tree3622af9225c4236c55b06444e67a82b19676e026
parent6146a0f1dfae5d37442a9ddcba012add260bceb0 (diff)
downloadlinux-a26a6c93edfeee82cb73f55e87d995eea59ddfe8.tar.gz
kbuild: Strip trailing padding bytes from modules.builtin.modinfo
After commit d50f21091358 ("kbuild: align modinfo section for Secureboot Authenticode EDK2 compat"), running modules_install with certain versions of kmod (such as 29.1 in Ubuntu Jammy) in certain configurations may fail with: depmod: ERROR: kmod_builtin_iter_next: unexpected string without modname prefix The additional padding bytes to ensure .modinfo is aligned within vmlinux.unstripped are unexpected by kmod, as this section has always just been null-terminated strings. Strip the trailing padding bytes from modules.builtin.modinfo after it has been extracted from vmlinux.unstripped to restore the format that kmod expects while keeping .modinfo aligned within vmlinux.unstripped to avoid regressing the Authenticode calculation fix for EDK2. Cc: stable@vger.kernel.org Fixes: d50f21091358 ("kbuild: align modinfo section for Secureboot Authenticode EDK2 compat") Reported-by: Omar Sandoval <osandov@fb.com> Reported-by: Samir M <samir@linux.ibm.com> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Closes: https://lore.kernel.org/7fef7507-ad64-4e51-9bb8-c9fb6532e51e@linux.ibm.com/ Tested-by: Omar Sandoval <osandov@fb.com> Tested-by: Samir M <samir@linux.ibm.com> Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Reviewed-by: Nicolas Schier <nsc@kernel.org> Link: https://patch.msgid.link/20251105-kbuild-fix-builtin-modinfo-for-kmod-v1-1-b419d8ad4606@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org>
-rw-r--r--scripts/Makefile.vmlinux15
1 files changed, 14 insertions, 1 deletions
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index ced4379550d766..cd788cac9d91da 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -102,11 +102,24 @@ 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' $@
+
OBJCOPYFLAGS_modules.builtin.modinfo := -j .modinfo -O binary
targets += modules.builtin.modinfo
modules.builtin.modinfo: vmlinux.unstripped FORCE
- $(call if_changed,objcopy)
+ $(call if_changed,modules_builtin_modinfo)
# modules.builtin
# ---------------------------------------------------------------------------