Misc objtool fixes:

- Bump up the Clang minimum version requirements
    for livepatch builds, due to Clang assembler
    section handling bugs causing silent
    miscompilations.
 
  - Strip livepatching symbol artifacts from
    non-livepatch modules.
 
  - Fix livepatch build warnings when certain
    Clang LTO options are enabled.
 
  - Fix livepatch build error when
    CONFIG_MEM_ALLOC_PROFILING_DEBUG=y.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-urgent-2026-02-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool fixes from Ingo Molnar::

 - Bump up the Clang minimum version requirements for livepatch
   builds, due to Clang assembler section handling bugs causing
   silent miscompilations

 - Strip livepatching symbol artifacts from non-livepatch modules

 - Fix livepatch build warnings when certain Clang LTO options
   are enabled

 - Fix livepatch build error when CONFIG_MEM_ALLOC_PROFILING_DEBUG=y

* tag 'objtool-urgent-2026-02-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool/klp: Fix unexported static call key access for manually built livepatch modules
  objtool/klp: Fix symbol correlation for orphaned local symbols
  livepatch: Free klp_{object,func}_ext data after initialization
  livepatch: Fix having __klp_objects relics in non-livepatch modules
  livepatch/klp-build: Require Clang assembler >= 20

include/linux/livepatch.h

@@ -175,6 +175,9 @@ int klp_enable_patch(struct klp_patch *);
 int klp_module_coming(struct module *mod);
 void klp_module_going(struct module *mod);
 
+void *klp_find_section_by_name(const struct module *mod, const char *name,
+			       size_t *sec_size);
+
 void klp_copy_process(struct task_struct *child);
 void klp_update_patch_state(struct task_struct *task);
 

kernel/livepatch/core.c

@@ -1356,6 +1356,25 @@ void klp_module_going(struct module *mod)
 	mutex_unlock(&klp_mutex);
 }
 
+void *klp_find_section_by_name(const struct module *mod, const char *name,
+			       size_t *sec_size)
+{
+	struct klp_modinfo *info = mod->klp_info;
+
+	for (int i = 1; i < info->hdr.e_shnum; i++) {
+		Elf_Shdr *shdr = &info->sechdrs[i];
+
+		if (!strcmp(info->secstrings + shdr->sh_name, name)) {
+			*sec_size = shdr->sh_size;
+			return (void *)shdr->sh_addr;
+		}
+	}
+
+	*sec_size = 0;
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(klp_find_section_by_name);
+
 static int __init klp_init(void)
 {
 	klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj);

scripts/livepatch/init.c

@@ -9,19 +9,19 @@
 #include <linux/slab.h>
 #include <linux/livepatch.h>
 
-extern struct klp_object_ext __start_klp_objects[];
-extern struct klp_object_ext __stop_klp_objects[];
-
 static struct klp_patch *patch;
 
 static int __init livepatch_mod_init(void)
 {
+	struct klp_object_ext *obj_exts;
+	size_t obj_exts_sec_size;
 	struct klp_object *objs;
 	unsigned int nr_objs;
 	int ret;
 
-	nr_objs = __stop_klp_objects - __start_klp_objects;
-
+	obj_exts = klp_find_section_by_name(THIS_MODULE, ".init.klp_objects",
+					    &obj_exts_sec_size);
+	nr_objs = obj_exts_sec_size / sizeof(*obj_exts);
 	if (!nr_objs) {
 		pr_err("nothing to patch!\n");
 		ret = -EINVAL;
@@ -41,7 +41,7 @@ static int __init livepatch_mod_init(void)
 	}
 
 	for (int i = 0; i < nr_objs; i++) {
-		struct klp_object_ext *obj_ext = __start_klp_objects + i;
+		struct klp_object_ext *obj_ext = obj_exts + i;
 		struct klp_func_ext *funcs_ext = obj_ext->funcs;
 		unsigned int nr_funcs = obj_ext->nr_funcs;
 		struct klp_func *funcs = objs[i].funcs;
@@ -90,12 +90,10 @@ err:
 
 static void __exit livepatch_mod_exit(void)
 {
-	unsigned int nr_objs;
+	struct klp_object *obj;
 
-	nr_objs = __stop_klp_objects - __start_klp_objects;
-
-	for (int i = 0; i < nr_objs; i++)
-		kfree(patch->objs[i].funcs);
+	klp_for_each_object_static(patch, obj)
+		kfree(obj->funcs);
 
 	kfree(patch->objs);
 	kfree(patch);

scripts/livepatch/klp-build

@@ -249,6 +249,10 @@ validate_config() {
 	[[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] &&	\
 		die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported"
 
+	[[ -v CONFIG_AS_IS_LLVM ]] &&				\
+		[[ "$CONFIG_AS_VERSION" -lt 200000 ]] &&	\
+		die "Clang assembler version < 20 not supported"
+
 	return 0
 }
 

scripts/module.lds.S

@@ -34,13 +34,8 @@ SECTIONS {
 
 	__patchable_function_entries : { *(__patchable_function_entries) }
 
-	__klp_funcs		0: ALIGN(8) { KEEP(*(__klp_funcs)) }
-
-	__klp_objects		0: ALIGN(8) {
-		__start_klp_objects = .;
-		KEEP(*(__klp_objects))
-		__stop_klp_objects = .;
-	}
+	.init.klp_funcs		0 : ALIGN(8) { KEEP(*(.init.klp_funcs)) }
+	.init.klp_objects	0 : ALIGN(8) { KEEP(*(.init.klp_objects)) }
 
 #ifdef CONFIG_ARCH_USES_CFI_TRAPS
 	__kcfi_traps		: { KEEP(*(.kcfi_traps)) }

tools/objtool/check.c

@@ -683,7 +683,7 @@ static int create_static_call_sections(struct objtool_file *file)
 
 		key_sym = find_symbol_by_name(file->elf, tmp);
 		if (!key_sym) {
-			if (!opts.module || file->klp) {
+			if (!opts.module) {
 				ERROR("static_call: can't find static_call_key symbol: %s", tmp);
 				return -1;
 			}
@@ -4762,7 +4762,7 @@ static int validate_ibt(struct objtool_file *file)
 		    !strcmp(sec->name, "__bug_table")			||
 		    !strcmp(sec->name, "__ex_table")			||
 		    !strcmp(sec->name, "__jump_table")			||
-		    !strcmp(sec->name, "__klp_funcs")			||
+		    !strcmp(sec->name, ".init.klp_funcs")		||
 		    !strcmp(sec->name, "__mcount_loc")			||
 		    !strcmp(sec->name, ".llvm.call-graph-profile")	||
 		    !strcmp(sec->name, ".llvm_bb_addr_map")		||

tools/objtool/include/objtool/klp.h

@@ -6,12 +6,12 @@
 #define SHN_LIVEPATCH		0xff20
 
 /*
- * __klp_objects and __klp_funcs are created by klp diff and used by the patch
- * module init code to build the klp_patch, klp_object and klp_func structs
- * needed by the livepatch API.
+ * .init.klp_objects and .init.klp_funcs are created by klp diff and used by the
+ * patch module init code to build the klp_patch, klp_object and klp_func
+ * structs needed by the livepatch API.
  */
-#define KLP_OBJECTS_SEC	"__klp_objects"
-#define KLP_FUNCS_SEC	"__klp_funcs"
+#define KLP_OBJECTS_SEC	".init.klp_objects"
+#define KLP_FUNCS_SEC	".init.klp_funcs"
 
 /*
  * __klp_relocs is an intermediate section which are created by klp diff and

tools/objtool/klp-diff.c

@@ -364,11 +364,40 @@ static int correlate_symbols(struct elfs *e)
 	struct symbol *file1_sym, *file2_sym;
 	struct symbol *sym1, *sym2;
 
-	/* Correlate locals */
-	for (file1_sym = first_file_symbol(e->orig),
-	     file2_sym = first_file_symbol(e->patched); ;
-	     file1_sym = next_file_symbol(e->orig, file1_sym),
-	     file2_sym = next_file_symbol(e->patched, file2_sym)) {
+	file1_sym = first_file_symbol(e->orig);
+	file2_sym = first_file_symbol(e->patched);
+
+	/*
+	 * Correlate any locals before the first FILE symbol.  This has been
+	 * seen when LTO inexplicably strips the initramfs_data.o FILE symbol
+	 * due to the file only containing data and no code.
+	 */
+	for_each_sym(e->orig, sym1) {
+		if (sym1 == file1_sym || !is_local_sym(sym1))
+			break;
+
+		if (dont_correlate(sym1))
+			continue;
+
+		for_each_sym(e->patched, sym2) {
+			if (sym2 == file2_sym || !is_local_sym(sym2))
+				break;
+
+			if (sym2->twin || dont_correlate(sym2))
+				continue;
+
+			if (strcmp(sym1->demangled_name, sym2->demangled_name))
+				continue;
+
+			sym1->twin = sym2;
+			sym2->twin = sym1;
+			break;
+		}
+	}
+
+	/* Correlate locals after the first FILE symbol */
+	for (; ; file1_sym = next_file_symbol(e->orig, file1_sym),
+		 file2_sym = next_file_symbol(e->patched, file2_sym)) {
 
 		if (!file1_sym && file2_sym) {
 			ERROR("FILE symbol mismatch: NULL != %s", file2_sym->name);
@@ -1436,7 +1465,7 @@ static int clone_special_sections(struct elfs *e)
 }
 
 /*
- * Create __klp_objects and __klp_funcs sections which are intermediate
+ * Create .init.klp_objects and .init.klp_funcs sections which are intermediate
  * sections provided as input to the patch module's init code for building the
  * klp_patch, klp_object and klp_func structs for the livepatch API.
  */