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SubjectRe: PATCH [1/1]: Don't return symbol lables in init sections after they have been freed
On Tue, 4 Mar 2008 18:47:15 -0500
Robin Getz <rgetz@blackfin.uclinux.org> wrote:

> From: Robin Getz <rgetz@blackfin.uclinux.org>
>
> Today, when module names are looked up, we do not qualify them (check to see
> if the init section is still active or not). This can lead to problems when
> kernel modules get loaded into the same address that the kernel init section
> (or other module's init section was at). We sometimes return the old / no
> lomnger there
>
> This leads to bogus OOPS messages, and developers wasting their time looking
> for problems (in the kernel init section) where there are none (since it was
> a module).
>
> This patch qualifies the addresses, to make sure the addresses are still valid
> before label/offset.
>
> Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
>
> ---
>
> linux-2.6.x/kernel/kallsyms.c | 3 ++-
> linux-2.6.x/kernel/module.c | 3 ++-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> Index: linux-2.6.x/kernel/kallsyms.c
> ===================================================================
> --- linux-2.6.x/kernel/kallsyms.c (revision 4212)
> +++ linux-2.6.x/kernel/kallsyms.c (working copy)
> @@ -42,7 +42,8 @@
>
> static inline int is_kernel_inittext(unsigned long addr)
> {
> - if (addr >= (unsigned long)_sinittext
> + if (system_state == SYSTEM_BOOTING
> + && addr >= (unsigned long)_sinittext
> && addr <= (unsigned long)_einittext)
> return 1;
> return 0;
> Index: linux-2.6.x/kernel/module.c
> ===================================================================
> --- linux-2.6.x/kernel/module.c (revision 4212)
> +++ linux-2.6.x/kernel/module.c (working copy)
> @@ -2121,7 +2121,8 @@
> struct module *mod;
>
> list_for_each_entry(mod, &modules, list) {
> - if (within(addr, mod->module_init, mod->init_size)
> + if ((within(addr, mod->module_init, mod->init_size)
> + && mod->state == MODULE_STATE_COMING)
> || within(addr, mod->module_core, mod->core_size)) {
> if (modname)
> *modname = mod->name;

Both of the above additions could do with a comment explaining what's going
on.

The first one perhaps should use the more specific initmem_now_dynamic
which is added by
gregkh-driver-warn-when-statically-allocated-kobjects-are-used.patch from
Greg's driver tree. If the intent is to merge that - if not perhaps it can
be split up.


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