diff options
| -rw-r--r-- | lib/Kconfig.debug | 2 | ||||
| -rw-r--r-- | scripts/Makefile.modpost | 1 | ||||
| -rw-r--r-- | scripts/mod/modpost.c | 255 |
3 files changed, 229 insertions, 29 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 748e72be6e6..c4ecb2994ba 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -108,6 +108,8 @@ config DEBUG_SECTION_MISMATCH will tell where the mismatch happens much closer to the source. The drawback is that we will report the same mismatch at least twice. + - Enable verbose reporting from modpost to help solving + the section mismatches reported. config DEBUG_KERNEL bool "Kernel debugging" diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index d988f5d21e3..65e707e1ffc 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -62,6 +62,7 @@ modpost = scripts/mod/modpost \ $(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \ $(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \ $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ + $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \ $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index e75739ec9c0..3cf1ba8220d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -28,6 +28,9 @@ static int vmlinux_section_warnings = 1; /* Only warn about unresolved symbols */ static int warn_unresolved = 0; /* How a symbol is exported */ +static int sec_mismatch_count = 0; +static int sec_mismatch_verbose = 1; + enum export { export_plain, export_unused, export_gpl, export_unused_gpl, export_gpl_future, export_unknown @@ -760,9 +763,23 @@ static const char *head_sections[] = { ".head.text*", NULL }; static const char *linker_symbols[] = { "__init_begin", "_sinittext", "_einittext", NULL }; +enum mismatch { + NO_MISMATCH, + TEXT_TO_INIT, + DATA_TO_INIT, + TEXT_TO_EXIT, + DATA_TO_EXIT, + XXXINIT_TO_INIT, + XXXEXIT_TO_EXIT, + INIT_TO_EXIT, + EXIT_TO_INIT, + EXPORT_TO_INIT_EXIT, +}; + struct sectioncheck { const char *fromsec[20]; const char *tosec[20]; + enum mismatch mismatch; }; const struct sectioncheck sectioncheck[] = { @@ -770,33 +787,54 @@ const struct sectioncheck sectioncheck[] = { * normal code and data */ { - .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL }, - .tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL } + .fromsec = { TEXT_SECTIONS, NULL }, + .tosec = { ALL_INIT_SECTIONS, NULL }, + .mismatch = TEXT_TO_INIT, +}, +{ + .fromsec = { DATA_SECTIONS, NULL }, + .tosec = { ALL_INIT_SECTIONS, NULL }, + .mismatch = DATA_TO_INIT, +}, +{ + .fromsec = { TEXT_SECTIONS, NULL }, + .tosec = { ALL_EXIT_SECTIONS, NULL }, + .mismatch = TEXT_TO_EXIT, +}, +{ + .fromsec = { DATA_SECTIONS, NULL }, + .tosec = { ALL_EXIT_SECTIONS, NULL }, + .mismatch = DATA_TO_EXIT, }, /* Do not reference init code/data from devinit/cpuinit/meminit code/data */ { .fromsec = { DEV_INIT_SECTIONS, CPU_INIT_SECTIONS, MEM_INIT_SECTIONS, NULL }, - .tosec = { INIT_SECTIONS, NULL } + .tosec = { INIT_SECTIONS, NULL }, + .mismatch = XXXINIT_TO_INIT, }, /* Do not reference exit code/data from devexit/cpuexit/memexit code/data */ { .fromsec = { DEV_EXIT_SECTIONS, CPU_EXIT_SECTIONS, MEM_EXIT_SECTIONS, NULL }, - .tosec = { EXIT_SECTIONS, NULL } + .tosec = { EXIT_SECTIONS, NULL }, + .mismatch = XXXEXIT_TO_EXIT, }, /* Do not use exit code/data from init code */ { .fromsec = { ALL_INIT_SECTIONS, NULL }, .tosec = { ALL_EXIT_SECTIONS, NULL }, + .mismatch = INIT_TO_EXIT, }, /* Do not use init code/data from exit code */ { .fromsec = { ALL_EXIT_SECTIONS, NULL }, - .tosec = { ALL_INIT_SECTIONS, NULL } + .tosec = { ALL_INIT_SECTIONS, NULL }, + .mismatch = EXIT_TO_INIT, }, /* Do not export init/exit functions or data */ { .fromsec = { "__ksymtab*", NULL }, - .tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL } + .tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }, + .mismatch = EXPORT_TO_INIT_EXIT } }; @@ -809,10 +847,10 @@ static int section_mismatch(const char *fromsec, const char *tosec) for (i = 0; i < elems; i++) { if (match(fromsec, check->fromsec) && match(tosec, check->tosec)) - return 1; + return check->mismatch; check++; } - return 0; + return NO_MISMATCH; } /** @@ -989,47 +1027,197 @@ static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr, } /* + * Convert a section name to the function/data attribute + * .init.text => __init + * .cpuinit.data => __cpudata + * .memexitconst => __memconst + * etc. +*/ +static char *sec2annotation(const char *s) +{ + if (match(s, init_exit_sections)) { + char *p = malloc(20); + char *r = p; + + *p++ = '_'; + *p++ = '_'; + if (*s == '.') + s++; + while (*s && *s != '.') + *p++ = *s++; + *p = '\0'; + if (*s == '.') + s++; + if (strstr(s, "rodata") != NULL) + strcat(p, "const "); + else if (strstr(s, "data") != NULL) + strcat(p, "data "); + else + strcat(p, " "); + return r; /* we leak her but we do not care */ + } else { + return ""; + } +} + +static int is_function(Elf_Sym *sym) +{ + if (sym) + return ELF_ST_TYPE(sym->st_info) == STT_FUNC; + else + return 0; +} + +/* * Print a warning about a section mismatch. * Try to find symbols near it so user can find it. * Check whitelist before warning - it may be a false positive. */ -static void report_sec_mismatch(const char *modname, +static void report_sec_mismatch(const char *modname, enum mismatch mismatch, const char *fromsec, unsigned long long fromaddr, const char *fromsym, - const char *tosec, const char *tosym) -{ - if (strlen(tosym)) { - warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s " - "in '%s'\n", - modname, fromsec, fromaddr, - tosec, tosym, fromsym); - } else { - warn("%s(%s+0x%llx): Section mismatch: reference to %s:%s\n", - modname, fromsec, fromaddr, - tosec, tosym); + int from_is_func, + const char *tosec, const char *tosym, + int to_is_func) +{ + const char *from, *from_p; + const char *to, *to_p; + from = from_is_func ? "function" : "variable"; + from_p = from_is_func ? "()" : ""; + to = to_is_func ? "function" : "variable"; + to_p = to_is_func ? "()" : ""; + + fprintf(stderr, "WARNING: %s(%s+0x%llx): Section mismatch in" + " reference from the %s %s%s to the %s %s:%s%s\n", + modname, fromsec, fromaddr, from, fromsym, from_p, + to, tosec, tosym, to_p); + + sec_mismatch_count++; + if (!sec_mismatch_verbose) + return; + + switch (mismatch) { + case TEXT_TO_INIT: + fprintf(stderr, + "The function %s %s() references\n" + "the %s %s%s%s.\n" + "This is often because %s lacks a %s\n" + "annotation or the annotation of %s is wrong.\n", + sec2annotation(fromsec), fromsym, + to, sec2annotation(tosec), tosym, to_p, + fromsym, sec2annotation(tosec), tosym); + break; + case DATA_TO_INIT: { + const char **s = symbol_white_list; + fprintf(stderr, + "The variable %s references\n" + "the %s %s%s%s\n" + "If the reference is valid then annotate the\n" + "variable with __init* (see linux/init.h) " + "or name the variable:\n", + fromsym, to, sec2annotation(tosec), tosym, to_p); + while (*s) + fprintf(stderr, "%s, ", *s++); + fprintf(stderr, "\n"); + break; } + case TEXT_TO_EXIT: + fprintf(stderr, + "The function %s() references a %s in an exit section.\n" + "Often the %s %s%s has valid usage outside the exit section\n" + "and the fix is to remove the %sannotation of %s.\n", + fromsym, to, to, tosym, to_p, sec2annotation(tosec), tosym); + break; + case DATA_TO_EXIT: { + const char **s = symbol_white_list; + fprintf(stderr, + "The variable %s references\n" + "the %s %s%s%s\n" + "If the reference is valid then annotate the\n" + "variable with __exit* (see linux/init.h) or " + "name the variable:\n", + fromsym, to, sec2annotation(tosec), tosym, to_p); + while (*s) + fprintf(stderr, "%s, ", *s++); + fprintf(stderr, "\n"); + break; + } + case XXXINIT_TO_INIT: + case XXXEXIT_TO_EXIT: + fprintf(stderr, + "The %s %s%s%s references\n" + "a %s %s%s%s.\n" + "If %s is only used by %s then\n" + "annotate %s with a matching annotation.\n", + from, sec2annotation(fromsec), fromsym, from_p, + to, sec2annotation(tosec), tosym, to_p, + fromsym, tosym, fromsym); + break; + case INIT_TO_EXIT: + fprintf(stderr, + "The %s %s%s%s references\n" + "a %s %s%s%s.\n" + "This is often seen when error handling " + "in the init function\n" + "uses functionality in the exit path.\n" + "The fix is often to remove the %sannotation of\n" + "%s%s so it may be used outside an exit section.\n", + from, sec2annotation(fromsec), fromsym, from_p, + to, sec2annotation(tosec), tosym, to_p, + sec2annotation(tosec), tosym, to_p); + break; + case EXIT_TO_INIT: + fprintf(stderr, + "The %s %s%s%s references\n" + "a %s %s%s%s.\n" + "This is often seen when error handling " + "in the exit function\n" + "uses functionality in the init path.\n" + "The fix is often to remove the %sannotation of\n" + "%s%s so it may be used outside an init section.\n", + from, sec2annotation(fromsec), fromsym, from_p, + to, sec2annotation(tosec), tosym, to_p, + sec2annotation(tosec), tosym, to_p); + break; + case EXPORT_TO_INIT_EXIT: + fprintf(stderr, + "The symbol %s is exported and annotated %s\n" + "Fix this by removing the %sannotation of %s " + "or drop the export.\n", + tosym, sec2annotation(tosec), sec2annotation(tosec), tosym); + case NO_MISMATCH: + /* To get warnings on missing members */ + break; + } + fprintf(stderr, "\n"); } static void check_section_mismatch(const char *modname, struct elf_info *elf, Elf_Rela *r, Elf_Sym *sym, const char *fromsec) { const char *tosec; + enum mismatch mismatch; tosec = sec_name(elf, sym->st_shndx); - if (section_mismatch(fromsec, tosec)) { - const char *fromsym; + mismatch = section_mismatch(fromsec, tosec); + if (mismatch != NO_MISMATCH) { + Elf_Sym *to; + Elf_Sym *from; const char *tosym; + const char *fromsym; - fromsym = sym_name(elf, - find_elf_symbol2(elf, r->r_offset, fromsec)); - tosym = sym_name(elf, - find_elf_symbol(elf, r->r_addend, sym)); + from = find_elf_symbol2(elf, r->r_offset, fromsec); + fromsym = sym_name(elf, from); + to = find_elf_symbol(elf, r->r_addend, sym); + tosym = sym_name(elf, to); /* check whitelist - we may ignore it */ if (secref_whitelist(fromsec, fromsym, tosec, tosym)) { - report_sec_mismatch(modname, fromsec, r->r_offset, - fromsym, tosec, tosym); + report_sec_mismatch(modname, mismatch, + fromsec, r->r_offset, fromsym, + is_function(from), tosec, tosym, + is_function(to)); } } } @@ -1643,7 +1831,7 @@ int main(int argc, char **argv) int opt; int err; - while ((opt = getopt(argc, argv, "i:I:mso:aw")) != -1) { + while ((opt = getopt(argc, argv, "i:I:msSo:aw")) != -1) { switch (opt) { case 'i': kernel_read = optarg; @@ -1664,6 +1852,9 @@ int main(int argc, char **argv) case 's': vmlinux_section_warnings = 0; break; + case 'S': + sec_mismatch_verbose = 0; + break; case 'w': warn_unresolved = 1; break; @@ -1708,6 +1899,12 @@ int main(int argc, char **argv) if (dump_write) write_dump(dump_write); + if (sec_mismatch_count && !sec_mismatch_verbose) + fprintf(stderr, "modpost: Found %d section mismatch(es).\n" + "To see additional details select \"Enable full " + "Section mismatch analysis\"\n" + "in the Kernel Hacking menu " + "(CONFIG_SECTION_MISMATCH).\n", sec_mismatch_count); return err; } |