From: Josh Poimboeuf Date: Tue, 10 Feb 2026 21:50:09 +0000 (-0800) Subject: objtool/klp: Fix detection of corrupt static branch/call entries X-Git-Tag: v7.0-rc4~9^2~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f9fb44b0ecefc1f218db56661ed66d4e8d67317d;p=thirdparty%2Flinux.git objtool/klp: Fix detection of corrupt static branch/call entries Patching a function which references a static key living in a kernel module is unsupported due to ordering issues inherent to late module patching: 1) Load a livepatch module which has a __jump_table entry which needs a klp reloc to reference static key K which lives in module M. 2) The __jump_table klp reloc does *not* get resolved because module M is not yet loaded. 3) jump_label_add_module() corrupts memory (or causes a panic) when dereferencing the uninitialized pointer to key K. validate_special_section_klp_reloc() intends to prevent that from ever happening by catching it at build time. However, it incorrectly assumes the special section entry's reloc symbol references have already been converted from section symbols to object symbols, causing the validation to miss corruption in extracted static branch/call table entries. Make sure the references have been properly converted before doing the validation. Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files") Reported-by: Song Liu Reviewed-and-tested-by: Song Liu Link: https://patch.msgid.link/124ad747b751df0df1725eff89de8332e3fb26d6.1770759954.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf --- diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c index 9f1f4011eb9c..d94632e80955 100644 --- a/tools/objtool/klp-diff.c +++ b/tools/objtool/klp-diff.c @@ -1364,6 +1364,9 @@ static int validate_special_section_klp_reloc(struct elfs *e, struct symbol *sym const char *sym_modname; struct export *export; + if (convert_reloc_sym(e->patched, reloc)) + continue; + /* Static branch/call keys are always STT_OBJECT */ if (reloc->sym->type != STT_OBJECT) {