objtool/klp: Fix cross-module klp relocation section naming

2026-08-11T23:10:51+00:00

A klp relocation section is .klp.rela.., where objname is the object being patched. klp-build wrongly derives objname from where the referenced symbol lives, not where it's referenced. For a cross-module reference like patched can_isotp code calling can.ko's can_rx_unregister(), that gives .klp.rela.can..text rather than .klp.rela.can_isotp..text. Unless the patch happens to patch can.ko as well, the relocation never gets applied and the call goes off into the weeds. Name the intermediate section __klp_relocs. so post-link can read the patched object's name from there. Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files") Reported-by: Joe Lawrence Link: https://lore.kernel.org/20260720145658.1103243-2-joe.lawrence@redhat.com Acked-by: Song Liu Acked-by: Joe Lawrence Link: https://patch.msgid.link/ee93a08f3e55e76ffa67d04e283917ddaa893f09.1786138493.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf

objtool/klp: Add post-link subcommand to finalize livepatch modules

2025-10-14T21:50:18+00:00

Livepatch needs some ELF magic which linkers don't like: - Two relocation sections (.rela*, .klp.rela*) for the same text section. - Use of SHN_LIVEPATCH to mark livepatch symbols. Unfortunately linkers tend to mangle such things. To work around that, klp diff generates a linker-compliant intermediate binary which encodes the relevant KLP section/reloc/symbol metadata. After module linking, the .ko then needs to be converted to an actual livepatch module. Introduce a new klp post-link subcommand to do so. Acked-by: Petr Mladek Tested-by: Joe Lawrence Signed-off-by: Josh Poimboeuf

kernel/git/stable/linux.git/tools/objtool/klp-post-link.c, branch master

objtool/klp: Fix cross-module klp relocation section naming

objtool/klp: Add post-link subcommand to finalize livepatch modules