On 09/30/2014 03:57 PM, Oleg Nesterov wrote: > On 09/30, Prarit Bhargava wrote: >> >> MODULE_STATE_UNFORMED needs to be separated into two states; one for the >> module load (MODULE_STATE_LOAD), and one for the module delete >> (MODULE_STATE_DELETE). > > And personally I think this makes sense in any case, but I can't really > comment the changes in this area. > >> @@ -3647,18 +3646,29 @@ static int m_show(struct seq_file *m, void *p) >> struct module *mod = list_entry(p, struct module, list); >> char buf[8]; >> >> - /* We always ignore unformed modules. */ >> - if (mod->state == MODULE_STATE_UNFORMED) >> + /* >> + * If the state is MODULE_STATE_LOAD then the module is in >> + * the early stages of loading. No information should be printed >> + * for this module as the data could be in an uninitialized state. >> + */ >> + if (mod->state == MODULE_STATE_LOAD) >> return 0; > > So this assumes that _UNFORMED state is fine... > > Not sure, but I can be easily wrong. For example, print_unload_info() -> > module_refcount() plays with mod->refptr, while free_module() does > module_unload_free() -> free_percpu(mod->refptr). No?
Oh geez -- I didn't see that in module_unload_free(). I had assumed that all the percpu data was free'd in free_module() call to percpu_modfree(mod) ... You're right though, the _DELETE state is not okay in this path, and if that's the case then I'm not sure we have to distinguish the two cases. > > Perhaps it makes sense to start with the simple patch for stable, > > + // sync with m_show() > + mutex_lock(module_mutex); > mod->state = MODULE_STATE_UNFORMED; > + mutex_unlock(module_mutex); > > then do a more sophisticated fix? I actually toyed around with this but thought that was too "hacky" for a fix. But if Rusty is okay with it, I'd be okay with it too. P. > > Oleg. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
