Messages in this thread | | | Date | Mon, 18 May 2015 10:22:21 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH v3] livepatch: Prevent to apply the patch once coming module notifier fails |
| |
On Mon, May 18, 2015 at 02:08:06PM +0200, Petr Mladek wrote: > On Wed 2015-05-13 09:14:15, Josh Poimboeuf wrote: > > On Tue, May 12, 2015 at 10:04:44PM +0800, Minfei Huang wrote: > > > @@ -930,6 +932,7 @@ disabled: > > > static int klp_module_notify(struct notifier_block *nb, unsigned long action, > > > void *data) > > > { > > > + int ret; > > > struct module *mod = data; > > > struct klp_patch *patch; > > > struct klp_object *obj; > > > @@ -955,7 +958,13 @@ static int klp_module_notify(struct notifier_block *nb, unsigned long action, > > > > > > if (action == MODULE_STATE_COMING) { > > > obj->mod = mod; > > > - klp_module_notify_coming(patch, obj); > > > + ret = klp_module_notify_coming(patch, obj); > > > + if (ret) { > > > + obj->mod = NULL; > > > + pr_warn("patch '%s' is dead, remove it " > > > + "or re-install the module '%s'\n", > > > + patch->mod->name, obj->name); > > > + } > > > > The patch isn't necessarily dead, since it might also include previously > > enabled changes for vmlinux or other modules. It can actually be a > > dangerous condition if there's a mismatch between old code in the module > > and new code elsewhere. How about something like: > > > > "patch '%s' is in an inconsistent state!\n" > > It must not be dangerous, otherwise the patch could not get applied > immediately. > > I would omit this message completely. It would just duplicate the > warning printed by klp_module_notify_coming().
This error path doesn't mean that the entire patch isn't applied. It only affects the subset of the patch which applies to the coming module. So you can have a dangerous mismatch in the case of a patch which patches multiple objects.
-- Josh
| |