Messages in this thread | | | Date | Wed, 27 Nov 2013 14:35:01 +0100 | From | Oleg Nesterov <> | Subject | Re: modules, add_kallsyms() && DEFINE_PER_CPU |
| |
On 11/27, Masami Hiramatsu wrote: > > (2013/11/27 2:50), Oleg Nesterov wrote: > > On 11/26, Oleg Nesterov wrote: > >> > >> Note: this doesn't work for modules, but module's per-cpu data is > >> not visible for kallsyms_lookup_name() anyway. > > > > Rusty, I am just curious if it makes sense to change this or not... > > > > But DEFINE_PER_CPU'ed symbols are ignored by add_kallsyms(). I guess > > this is because is_core_symbol() requires "sh_flags & SHF_ALLOC". > > And probably because of INIT_OFFSET_MASK. > > Oleg, I think you can do it by using is_module_percpu_address(). :)
Not only is_module_percpu_address() can't help. We can solve the is-it-percpu problem (although the check won't be cheap).
The problem is, sc->addr is always NULL if DEFINE_PER_CPU() was used in a module. kallsyms_lookup_name() can never see it because it is ignored by add_kallsyms(), it is nacked by is_core_symbol().
IOW, with or without this patch @modular_percpu_sym never reads the memory.
Oleg.
| |