diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2020-02-17 21:41:54 -0600 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-02-21 10:20:34 +0100 |
| commit | 7acfe5315312fc56c2a94c9216448087b38ae909 (patch) | |
| tree | e3187f3209664e907dabf0fa7a0151d1a82e487f /tools/objtool | |
| parent | 113d4bc9048336ba7c3d2ad972dbad4aef6e148a (diff) | |
objtool: Improve call destination function detection
A recent clang change, combined with a binutils bug, can trigger a
situation where a ".Lprintk$local" STT_NOTYPE symbol gets created at the
same offset as the "printk" STT_FUNC symbol. This confuses objtool:
kernel/printk/printk.o: warning: objtool: ignore_loglevel_setup()+0x10: can't find call dest symbol at .text+0xc67
Improve the call destination detection by looking specifically for an
STT_FUNC symbol.
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/872
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=25551
Link: https://lkml.kernel.org/r/0a7ee320bc0ea4469bd3dc450a7b4725669e0ea9.1581997059.git.jpoimboe@redhat.com
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/check.c | 27 | ||||
| -rw-r--r-- | tools/objtool/elf.c | 14 | ||||
| -rw-r--r-- | tools/objtool/elf.h | 1 |
3 files changed, 31 insertions, 11 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4d6e283951ec..6b6178ef4464 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -420,8 +420,8 @@ static void add_ignores(struct objtool_file *file) break; case STT_SECTION: - func = find_symbol_by_offset(rela->sym->sec, rela->addend); - if (!func || func->type != STT_FUNC) + func = find_func_by_offset(rela->sym->sec, rela->addend); + if (!func) continue; break; @@ -665,10 +665,14 @@ static int add_call_destinations(struct objtool_file *file) insn->len); if (!rela) { dest_off = insn->offset + insn->len + insn->immediate; - insn->call_dest = find_symbol_by_offset(insn->sec, - dest_off); + insn->call_dest = find_func_by_offset(insn->sec, dest_off); + if (!insn->call_dest) + insn->call_dest = find_symbol_by_offset(insn->sec, dest_off); - if (!insn->call_dest && !insn->ignore) { + if (insn->ignore) + continue; + + if (!insn->call_dest) { WARN_FUNC("unsupported intra-function call", insn->sec, insn->offset); if (retpoline) @@ -676,11 +680,16 @@ static int add_call_destinations(struct objtool_file *file) return -1; } + if (insn->func && insn->call_dest->type != STT_FUNC) { + WARN_FUNC("unsupported call to non-function", + insn->sec, insn->offset); + return -1; + } + } else if (rela->sym->type == STT_SECTION) { - insn->call_dest = find_symbol_by_offset(rela->sym->sec, - rela->addend+4); - if (!insn->call_dest || - insn->call_dest->type != STT_FUNC) { + insn->call_dest = find_func_by_offset(rela->sym->sec, + rela->addend+4); + if (!insn->call_dest) { WARN_FUNC("can't find call dest symbol at %s+0x%x", insn->sec, insn->offset, rela->sym->sec->name, diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index edba4745f25a..cc4601c879ce 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -62,8 +62,18 @@ struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset) struct symbol *sym; list_for_each_entry(sym, &sec->symbol_list, list) - if (sym->type != STT_SECTION && - sym->offset == offset) + if (sym->type != STT_SECTION && sym->offset == offset) + return sym; + + return NULL; +} + +struct symbol *find_func_by_offset(struct section *sec, unsigned long offset) +{ + struct symbol *sym; + + list_for_each_entry(sym, &sec->symbol_list, list) + if (sym->type == STT_FUNC && sym->offset == offset) return sym; return NULL; diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h index 44150204db4d..a1963259b930 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -77,6 +77,7 @@ struct elf { struct elf *elf_read(const char *name, int flags); struct section *find_section_by_name(struct elf *elf, const char *name); +struct symbol *find_func_by_offset(struct section *sec, unsigned long offset); struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset); struct symbol *find_symbol_by_name(struct elf *elf, const char *name); struct symbol *find_symbol_containing(struct section *sec, unsigned long offset); |