This may not be a practical problem, but the second pass of ARCH=i386 modpost causes segmentation fault if the -s option is not passed. MODPOST 12 modules Segmentation fault (core dumped) make[2]: *** [scripts/Makefile.modpost:94: __modpost] Error 139 make[1]: *** [Makefile:1339: modules] Error 2 make[1]: *** Waiting for unfinished jobs.... The segmentation fault occurs when section_rel() is called for vmlinux, which is untested in regular builds. The cause of the problem is reloc_location() returning a wrong pointer for ET_EXEC object type. In this case, you need to subtract sechdr->sh_addr, otherwise it would get access beyond the mmap'ed memory. Add sym_get_data_by_offset() helper to avoid code duplication.
Unified · Split
| @@ -300,19 +300,23 @@ static const char *sec_name(struct elf_info *elf, int secindex) · 299 unmodified lines | |||
| 300 | return sech_name(elf, &elf->sechdrs[secindex]); | 300 | return sech_name(elf, &elf->sechdrs[secindex]); |
| 301 | } | 301 | } |
| 302 | 302 | ||
| 303 | static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym) | 303 | static void *sym_get_data_by_offset(const struct elf_info *info, |
| 304 | unsigned int secindex, unsigned long offset) | ||
| 304 | { | 305 | { |
| 305 | unsigned int secindex = get_secindex(info, sym); | ||
| 306 | Elf_Shdr *sechdr = &info->sechdrs[secindex]; | 306 | Elf_Shdr *sechdr = &info->sechdrs[secindex]; |
| 307 | unsigned long offset; | ||
| 308 | 307 | ||
| 309 | offset = sym->st_value; | ||
| 310 | if (info->hdr->e_type != ET_REL) | 308 | if (info->hdr->e_type != ET_REL) |
| 311 | offset -= sechdr->sh_addr; | 309 | offset -= sechdr->sh_addr; |
| 312 | 310 | ||
| 313 | return (void *)info->hdr + sechdr->sh_offset + offset; | 311 | return (void *)info->hdr + sechdr->sh_offset + offset; |
| 314 | } | 312 | } |
| 315 | 313 | ||
| 314 | static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym) | ||
| 315 | { | ||
| 316 | return sym_get_data_by_offset(info, get_secindex(info, sym), | ||
| 317 | sym->st_value); | ||
| 318 | } | ||
| 319 | |||
| 316 | #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) | 320 | #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0) |
| 317 | 321 | ||
| 318 | static enum export export_from_secname(struct elf_info *elf, unsigned int sec) | 322 | static enum export export_from_secname(struct elf_info *elf, unsigned int sec) |
| @@ -1752,11 +1756,7 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, · 1433 unmodified lines | |||
| 1752 | static unsigned int *reloc_location(struct elf_info *elf, | 1756 | static unsigned int *reloc_location(struct elf_info *elf, |
| 1753 | Elf_Shdr *sechdr, Elf_Rela *r) | 1757 | Elf_Shdr *sechdr, Elf_Rela *r) |
| 1754 | { | 1758 | { |
| 1755 | Elf_Shdr *sechdrs = elf->sechdrs; | 1759 | return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset); |
| 1756 | int section = sechdr->sh_info; | ||
| 1757 | |||
| 1758 | return (void *)elf->hdr + sechdrs[section].sh_offset + | ||
| 1759 | r->r_offset; | ||
| 1760 | } | 1760 | } |
| 1761 | 1761 | ||
| 1762 | static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) | 1762 | static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r) |