Re: Strange output from exportfs in 2.6.5-rc3-mm1

Andrew Morton
2004-04-01T05:39:18Z

"Randy.Dunlap" <rddunlap@osdl.org> wrote:
>
> On Wed, 31 Mar 2004 11:04:39 +0800 Yusuf Goolamabbas wrote:
>
> | In 2.6.5-rc3-mm1, I saw the following via dmesg
> |
> | exportfs: no version for "init_module" found: kernel tainted.
> |
> | I am exporting a few filesystems via NFS but this is the first 2.6.x
> | kernel in which I have seen the above message
> | Output of lsmod
> |
> | nfsd 94344 -
> | exportfs 5440 -
> | lockd 59912 -
> | sunrpc 134312 -
> | e100 28196 -
> | ext3 116104 -
> | jbd 55416 -
> | aic7xxx 164588 -
> | sd_mod 17696 -
> | scsi_mod 109200 -
>
> I can't reproduce that with 2.6.5-rc3-mm3 (but there are no
> changes to exportfs in -mm3).

You probably didn't have modversions enabled?

Rusty sent me this:

From: Rusty Russell <rusty@rustcorp.com.au>

Brian Gerst's patch which moved __this_module out from module.h into the
module post-processing had a side effect. genksyms didn't see the
undefined symbols for modules without a module_init (or module_exit), and
hence didn't generate a version for them, causing the kernel to be tainted.

The simple solution is to always include the versions for these functions.
Also includes two cleanups:

1) alloc_symbol is easier to use if it populates ->next for us.

2) add_exported_symbol should set owner to module, not head of module
list (we don't use this field in entries in that list, fortunately).

---

25-akpm/scripts/modpost.c | 35 ++++++++++++++++-------------------
1 files changed, 16 insertions(+), 19 deletions(-)

diff -puN scripts/modpost.c~modversions-fix scripts/modpost.c
--- 25/scripts/modpost.c~modversions-fix 2004-03-31 21:37:47.745773896 -0800
+++ 25-akpm/scripts/modpost.c 2004-03-31 21:37:47.749773288 -0800
@@ -113,12 +113,13 @@ static inline unsigned int tdb_hash(cons
* the list of unresolved symbols per module */

struct symbol *
-alloc_symbol(const char *name)
+alloc_symbol(const char *name, struct symbol *next)
{
struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));

memset(s, 0, sizeof(*s));
strcpy(s->name, name);
+ s->next = next;
return s;
}

@@ -128,17 +129,15 @@ void
new_symbol(const char *name, struct module *module, unsigned int *crc)
{
unsigned int hash;
- struct symbol *new = alloc_symbol(name);
+ struct symbol *new;

+ hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
+ new = symbolhash[hash] = alloc_symbol(name, symbolhash[hash]);
new->module = module;
if (crc) {
new->crc = *crc;
new->crc_valid = 1;
}
-
- hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
- new->next = symbolhash[hash];
- symbolhash[hash] = new;
}

#define DOTSYM_PFX "__dot_"
@@ -177,7 +176,7 @@ add_exported_symbol(const char *name, st
struct symbol *s = find_symbol(name);

if (!s) {
- new_symbol(name, modules, crc);
+ new_symbol(name, module, crc);
return;
}
if (crc) {
@@ -331,7 +330,6 @@ void
handle_modversions(struct module *mod, struct elf_info *info,
Elf_Sym *sym, const char *symname)
{
- struct symbol *s;
unsigned int crc;

switch (sym->st_shndx) {
@@ -368,13 +366,10 @@ handle_modversions(struct module *mod, s
#endif

if (memcmp(symname, MODULE_SYMBOL_PREFIX,
- strlen(MODULE_SYMBOL_PREFIX)) == 0) {
- s = alloc_symbol(symname +
- strlen(MODULE_SYMBOL_PREFIX));
- /* add to list */
- s->next = mod->unres;
- mod->unres = s;
- }
+ strlen(MODULE_SYMBOL_PREFIX)) == 0)
+ mod->unres = alloc_symbol(symname +
+ strlen(MODULE_SYMBOL_PREFIX),
+ mod->unres);
break;
default:
/* All exported symbols */
@@ -431,10 +426,12 @@ read_symbols(char *modname)
* the automatic versioning doesn't pick it up, but it's really
* important anyhow */
if (modversions) {
- s = alloc_symbol("struct_module");
- /* add to list */
- s->next = mod->unres;
- mod->unres = s;
+ mod->unres = alloc_symbol("struct_module", mod->unres);
+
+ /* Always version init_module and cleanup_module, in
+ * case module doesn't have its own. */
+ mod->unres = alloc_symbol("init_module", mod->unres);
+ mod->unres = alloc_symbol("cleanup_module", mod->unres);
}
}

_