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    SubjectRe: PATCH [1/1]: Don't return symbol lables in init sections after they have been freed
    On Tue, Mar 04, 2008 at 04:05:01PM -0800, Andrew Morton wrote:
    > 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.

    The intent wasn't to merge that, as it seemed like a big hack. But if
    people don't mind, I have no objection to it going in.

    thanks,

    greg k-h


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