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authorTiezhu Yang <yangtiezhu@loongson.cn>2024-03-11 17:23:47 +0300
committerHuacai Chen <chenhuacai@loongson.cn>2024-03-11 17:23:47 +0300
commite91c5e4c21b0339376ee124cda5c9b27d41f2cbc (patch)
tree68c9c3aba90b0c4ea61ef5b0ec1c115551d9b62a /tools/objtool
parentd5ab2bc36c6b0ce2f3409f934ff9cdf6d6768fa2 (diff)
downloadlinux-e91c5e4c21b0339376ee124cda5c9b27d41f2cbc.tar.xz
objtool: Check local label in read_unwind_hints()
When update the latest upstream gcc and binutils, it generates some objtool warnings on LoongArch, like this: arch/loongarch/kernel/entry.o: warning: objtool: ret_from_fork+0x0: unreachable instruction We can see that the reloc sym name is local label instead of section in relocation section '.rela.discard.unwind_hints', in this case, the reloc sym type is STT_NOTYPE instead of STT_SECTION. Let us check it to not return -1, then use reloc->sym->offset instead of reloc addend which is 0 to find the corresponding instruction. Here are some detailed info: [fedora@linux 6.8.test]$ gcc --version gcc (GCC) 14.0.1 20240129 (experimental) [fedora@linux 6.8.test]$ as --version GNU assembler (GNU Binutils) 2.42.50.20240129 [fedora@linux 6.8.test]$ readelf -r arch/loongarch/kernel/entry.o | grep -A 3 "rela.discard.unwind_hints" Relocation section '.rela.discard.unwind_hints' at offset 0x3a8 contains 7 entries: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 000a00000063 R_LARCH_32_PCREL 0000000000000000 .Lhere_1 + 0 00000000000c 000b00000063 R_LARCH_32_PCREL 00000000000000a8 .Lhere_50 + 0 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'tools/objtool')
-rw-r--r--tools/objtool/check.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d0e82c729dd9..1009d144f756 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2227,6 +2227,7 @@ static int read_unwind_hints(struct objtool_file *file)
struct unwind_hint *hint;
struct instruction *insn;
struct reloc *reloc;
+ unsigned long offset;
int i;
sec = find_section_by_name(file->elf, ".discard.unwind_hints");
@@ -2254,7 +2255,16 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}
- insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+ if (reloc->sym->type == STT_SECTION) {
+ offset = reloc_addend(reloc);
+ } else if (reloc->sym->local_label) {
+ offset = reloc->sym->offset;
+ } else {
+ WARN("unexpected relocation symbol type in %s", sec->rsec->name);
+ return -1;
+ }
+
+ insn = find_insn(file, reloc->sym->sec, offset);
if (!insn) {
WARN("can't find insn for unwind_hints[%d]", i);
return -1;