On Mon, 9 Feb 2015, Josh Poimboeuf wrote: > If registering the function with ftrace has previously succeeded, > unregistering will almost never fail. Even if it does, it's not a fatal > error. We can still carry on and disable the klp_func from being used > by removing it from the klp_ops func stack. > > Signed-off-by: Josh Poimboeuf <[email protected]>
This makes sense, so Reviewed-by: Miroslav Benes <[email protected]> I think this patch could be taken independently of the consistency model. If no one else has any objection... Miroslav > --- > kernel/livepatch/core.c | 67 > +++++++++++++------------------------------------ > 1 file changed, 17 insertions(+), 50 deletions(-) > > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c > index 9adf86b..081df77 100644 > --- a/kernel/livepatch/core.c > +++ b/kernel/livepatch/core.c > @@ -322,32 +322,20 @@ static void notrace klp_ftrace_handler(unsigned long ip, > klp_arch_set_pc(regs, (unsigned long)func->new_func); > } > > -static int klp_disable_func(struct klp_func *func) > +static void klp_disable_func(struct klp_func *func) > { > struct klp_ops *ops; > - int ret; > - > - if (WARN_ON(func->state != KLP_ENABLED)) > - return -EINVAL; > > - if (WARN_ON(!func->old_addr)) > - return -EINVAL; > + WARN_ON(func->state != KLP_ENABLED); > + WARN_ON(!func->old_addr); > > ops = klp_find_ops(func->old_addr); > if (WARN_ON(!ops)) > - return -EINVAL; > + return; > > if (list_is_singular(&ops->func_stack)) { > - ret = unregister_ftrace_function(&ops->fops); > - if (ret) { > - pr_err("failed to unregister ftrace handler for > function '%s' (%d)\n", > - func->old_name, ret); > - return ret; > - } > - > - ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0); > - if (ret) > - pr_warn("function unregister succeeded but failed to > clear the filter\n"); > + WARN_ON(unregister_ftrace_function(&ops->fops)); > + WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0)); > > list_del_rcu(&func->stack_node); > list_del(&ops->node); > @@ -357,8 +345,6 @@ static int klp_disable_func(struct klp_func *func) > } > > func->state = KLP_DISABLED; > - > - return 0; > } > > static int klp_enable_func(struct klp_func *func) > @@ -419,23 +405,15 @@ err: > return ret; > } > > -static int klp_disable_object(struct klp_object *obj) > +static void klp_disable_object(struct klp_object *obj) > { > struct klp_func *func; > - int ret; > > - for (func = obj->funcs; func->old_name; func++) { > - if (func->state != KLP_ENABLED) > - continue; > - > - ret = klp_disable_func(func); > - if (ret) > - return ret; > - } > + for (func = obj->funcs; func->old_name; func++) > + if (func->state == KLP_ENABLED) > + klp_disable_func(func); > > obj->state = KLP_DISABLED; > - > - return 0; > } > > static int klp_enable_object(struct klp_object *obj) > @@ -451,22 +429,19 @@ static int klp_enable_object(struct klp_object *obj) > > for (func = obj->funcs; func->old_name; func++) { > ret = klp_enable_func(func); > - if (ret) > - goto unregister; > + if (ret) { > + klp_disable_object(obj); > + return ret; > + } > } > obj->state = KLP_ENABLED; > > return 0; > - > -unregister: > - WARN_ON(klp_disable_object(obj)); > - return ret; > } > > static int __klp_disable_patch(struct klp_patch *patch) > { > struct klp_object *obj; > - int ret; > > /* enforce stacking: only the last enabled patch can be disabled */ > if (!list_is_last(&patch->list, &klp_patches) && > @@ -476,12 +451,8 @@ static int __klp_disable_patch(struct klp_patch *patch) > pr_notice("disabling patch '%s'\n", patch->mod->name); > > for (obj = patch->objs; obj->funcs; obj++) { > - if (obj->state != KLP_ENABLED) > - continue; > - > - ret = klp_disable_object(obj); > - if (ret) > - return ret; > + if (obj->state == KLP_ENABLED) > + klp_disable_object(obj); > } > > patch->state = KLP_DISABLED; > @@ -931,7 +902,6 @@ static void klp_module_notify_going(struct klp_patch > *patch, > { > struct module *pmod = patch->mod; > struct module *mod = obj->mod; > - int ret; > > if (patch->state == KLP_DISABLED) > goto disabled; > @@ -939,10 +909,7 @@ static void klp_module_notify_going(struct klp_patch > *patch, > pr_notice("reverting patch '%s' on unloading module '%s'\n", > pmod->name, mod->name); > > - ret = klp_disable_object(obj); > - if (ret) > - pr_warn("failed to revert patch '%s' on module '%s' (%d)\n", > - pmod->name, mod->name, ret); > + klp_disable_object(obj); > > disabled: > klp_free_object_loaded(obj); > -- > 2.1.0 > > -- > 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/ > -- 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/
