(2014/03/24 23:59), Steven Rostedt wrote: > On Mon, 24 Mar 2014 20:26:05 +0900 > Masami Hiramatsu <masami.hiramatsu...@hitachi.com> wrote: > > >> Thank you for reporting with this pretty backtrace :) >> Steven, I think this is not the kprobe bug but ftrace (and perhaps, module). > > Looks to be more of a module issue than a ftrace issue. > >> >> If the ftrace can set loading module text read only before the module >> subsystem >> expected, I think it should be protected by the module subsystem itself >> (e.g. set_all_modules_text_ro(rw) skips the modules which is >> MODULE_STATE_COMING) >> > > Does this patch fix it?
Yep, I tested using my reproducer and confirmed that this patch fixed this issue, thanks! Thanks, Takao Indoh > > In-review-off-by: Steven Rostedt <rost...@goodmis.org> > > diff --git a/include/linux/module.h b/include/linux/module.h > index 5a50539..a1acabf 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -207,10 +207,11 @@ struct module_use { > }; > > enum module_state { > - MODULE_STATE_LIVE, /* Normal state. */ > - MODULE_STATE_COMING, /* Full formed, running module_init. */ > - MODULE_STATE_GOING, /* Going away. */ > - MODULE_STATE_UNFORMED, /* Still setting it up. */ > + MODULE_STATE_LIVE, /* Normal state. */ > + MODULE_STATE_COMING, /* Full formed, running module_init. */ > + MODULE_STATE_COMING_FINAL, /* Ready to be changed to read only. */ > + MODULE_STATE_GOING, /* Going away. */ > + MODULE_STATE_UNFORMED, /* Still setting it up. */ > }; > > /** > diff --git a/kernel/module.c b/kernel/module.c > index d24fcf2..0905bed 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -1805,7 +1805,8 @@ void set_all_modules_text_ro(void) > > mutex_lock(&module_mutex); > list_for_each_entry_rcu(mod, &modules, list) { > - if (mod->state == MODULE_STATE_UNFORMED) > + if (mod->state == MODULE_STATE_UNFORMED || > + mod->state == MODULE_STATE_COMING) > continue; > if ((mod->module_core) && (mod->core_text_size)) { > set_page_attributes(mod->module_core, > @@ -3020,6 +3021,13 @@ static int do_init_module(struct module *mod) > blocking_notifier_call_chain(&module_notify_list, > MODULE_STATE_COMING, mod); > > + /* > + * This module must not be changed by set_all_modules_text_ro() > + * until we get here. Otherwise notifiers that change text > + * (like ftrace does) will break. > + */ > + mod->state = MODULE_STATE_COMING_FINAL; > + > /* Set RO and NX regions for core */ > set_section_ro_nx(mod->module_core, > mod->core_text_size, > > > -- 印藤隆夫(INDOH Takao) E-Mail : indou.ta...@jp.fujitsu.com TEL : 7551-4832(055-924-7241) 富士通(株) PFソ事本)Linux開発統括部 開発部 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/