kbuild: add verbose option to Section mismatch reporting in modpost
If the config option CONFIG_SECTION_MISMATCH is not set and
we see a Section mismatch present the following to the user:
modpost: Found 1 section mismatch(es).
To see additional details select "Enable full Section mismatch analysis"
in the Kernel Hacking menu (CONFIG_SECTION_MISMATCH).
If the option CONFIG_SECTION_MISMATCH is selected
then be verbose in the Section mismatch reporting from mdopost.
Sample outputs:
WARNING: o-x86_64/vmlinux.o(.text+0x7396): Section mismatch in reference from the function discover_ebda() to the variable .init.data:ebda_addr
The function discover_ebda() references
the variable __initdata ebda_addr.
This is often because discover_ebda lacks a __initdata
annotation or the annotation of ebda_addr is wrong.
WARNING: o-x86_64/vmlinux.o(.data+0x74d58): Section mismatch in reference from the variable pci_serial_quirks to the function .devexit.text:pci_plx9050_exit()
The variable pci_serial_quirks references
the function __devexit pci_plx9050_exit()
If the reference is valid then annotate the
variable with __exit* (see linux/init.h) or name the variable:
*driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console,
WARNING: o-x86_64/vmlinux.o(__ksymtab+0x630): Section mismatch in reference from the variable __ksymtab_arch_register_cpu to the function .cpuinit.text:arch_register_cpu()
The symbol arch_register_cpu is exported and annotated __cpuinit
Fix this by removing the __cpuinit annotation of arch_register_cpu or drop the export.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index e75739e..3cf1ba8 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -28,6 +28,9 @@
/* 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 *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 @@
* 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 @@
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 @@
}
/*
+ * 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)
+ int from_is_func,
+ const char *tosec, const char *tosym,
+ int to_is_func)
{
- 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);
+ 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 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 @@
case 's':
vmlinux_section_warnings = 0;
break;
+ case 'S':
+ sec_mismatch_verbose = 0;
+ break;
case 'w':
warn_unresolved = 1;
break;
@@ -1708,6 +1899,12 @@
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;
}