Commit 768895fb authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'objtool-urgent-2021-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull objtool fixes from Ingo Molnar:
 "Two objtool fixes:

   - fix a bug that corrupts the code by mistakenly rewriting
     conditional jumps

   - fix another bug generating an incorrect ELF symbol table
     during retpoline rewriting"

* tag 'objtool-urgent-2021-06-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Only rewrite unconditional retpoline thunk calls
  objtool: Fix .symtab_shndx handling for elf_create_undef_symbol()
parents ad347abe 2d49b721

tools/objtool/arch/x86/decode.c

+4 −0
Original line number Diff line number Diff line
@@ -747,6 +747,10 @@ int arch_rewrite_retpolines(struct objtool_file *file) 


	list_for_each_entry(insn, &file->retpoline_call_list, call_node) {



		if (insn->type != INSN_JUMP_DYNAMIC &&

		    insn->type != INSN_CALL_DYNAMIC)

			continue;



		if (!strcmp(insn->sec->name, ".text.__x86.indirect_thunk"))

			continue;

tools/objtool/elf.c

+24 −1
Original line number Diff line number Diff line
@@ -717,7 +717,7 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str) 


struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)

{

	struct section *symtab;

	struct section *symtab, *symtab_shndx;

	struct symbol *sym;

	Elf_Data *data;

	Elf_Scn *s;
@@ -769,6 +769,29 @@ struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name) 
	symtab->len += data->d_size;

	symtab->changed = true;



	symtab_shndx = find_section_by_name(elf, ".symtab_shndx");

	if (symtab_shndx) {

		s = elf_getscn(elf->elf, symtab_shndx->idx);

		if (!s) {

			WARN_ELF("elf_getscn");

			return NULL;

		}



		data = elf_newdata(s);

		if (!data) {

			WARN_ELF("elf_newdata");

			return NULL;

		}



		data->d_buf = &sym->sym.st_size; /* conveniently 0 */

		data->d_size = sizeof(Elf32_Word);

		data->d_align = 4;

		data->d_type = ELF_T_WORD;



		symtab_shndx->len += 4;

		symtab_shndx->changed = true;

	}



	sym->sec = find_section_by_index(elf, 0);



	elf_add_symbol(elf, sym);