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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching

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Pull livepatching update from Jiri Kosina:

 - cleanup of module notifiers; this depends on a module.c cleanup which
   has been acked by Rusty; from Jessica Yu

 - small assorted fixes and MAINTAINERS update

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch/module: remove livepatch module notifier
  modules: split part of complete_formation() into prepare_coming_module()
  livepatch: Update maintainers
  livepatch: Fix the error message about unresolvable ambiguity
  klp: remove CONFIG_LIVEPATCH dependency from klp headers
  klp: remove superfluous errors in asm/livepatch.h
This commit is contained in:
Linus Torvalds 2016-03-17 21:46:32 -07:00
commit 0f49fc95b8
6 changed files with 123 additions and 106 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
MAINTAINERS
View File

@ -6596,9 +6596,10 @@ F: drivers/platform/x86/hp_accel.c
LIVE PATCHING
M: Josh Poimboeuf <jpoimboe@redhat.com>
M: Seth Jennings <sjenning@redhat.com>
M: Jessica Yu <jeyu@redhat.com>
M: Jiri Kosina <jikos@kernel.org>
M: Vojtech Pavlik <vojtech@suse.com>
M: Miroslav Benes <mbenes@suse.cz>
R: Petr Mladek <pmladek@suse.com>
S: Maintained
F: kernel/livepatch/
F: include/linux/livepatch.h

4
arch/s390/include/asm/livepatch.h
View File

@ -19,7 +19,6 @@
#include <linux/module.h>
#ifdef CONFIG_LIVEPATCH
static inline int klp_check_compiler_support(void)
{
return 0;
@ -36,8 +35,5 @@ static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
regs->psw.addr = ip;
}
#else
#error Include linux/livepatch.h, not asm/livepatch.h
#endif
#endif

4
arch/x86/include/asm/livepatch.h
View File

@ -25,7 +25,6 @@
#include <linux/module.h>
#include <linux/ftrace.h>
#ifdef CONFIG_LIVEPATCH
static inline int klp_check_compiler_support(void)
{
#ifndef CC_USING_FENTRY
@ -40,8 +39,5 @@ static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
regs->ip = ip;
}
#else
#error Include linux/livepatch.h, not asm/livepatch.h
#endif
#endif /* _ASM_X86_LIVEPATCH_H */

9
include/linux/livepatch.h
View File

@ -134,6 +134,15 @@ int klp_unregister_patch(struct klp_patch *);
int klp_enable_patch(struct klp_patch *);
int klp_disable_patch(struct klp_patch *);
/* Called from the module loader during module coming/going states */
int klp_module_coming(struct module *mod);
void klp_module_going(struct module *mod);
#else /* !CONFIG_LIVEPATCH */
static inline int klp_module_coming(struct module *mod) { return 0; }
static inline void klp_module_going(struct module *mod) { }
#endif /* CONFIG_LIVEPATCH */
#endif /* _LINUX_LIVEPATCH_H_ */

171
kernel/livepatch/core.c
View File

@ -99,12 +99,12 @@ static void klp_find_object_module(struct klp_object *obj)
/*
* We do not want to block removal of patched modules and therefore
* we do not take a reference here. The patches are removed by
* a going module handler instead.
* klp_module_going() instead.
*/
mod = find_module(obj->name);
/*
* Do not mess work of the module coming and going notifiers.
* Note that the patch might still be needed before the going handler
* Do not mess work of klp_module_coming() and klp_module_going().
* Note that the patch might still be needed before klp_module_going()
* is called. Module functions can be called even in the GOING state
* until mod->exit() finishes. This is especially important for
* patches that modify semantic of the functions.
@ -190,8 +190,8 @@ static int klp_find_object_symbol(const char *objname, const char *name,
if (args.addr == 0)
pr_err("symbol '%s' not found in symbol table\n", name);
else if (args.count > 1 && sympos == 0) {
pr_err("unresolvable ambiguity (%lu matches) on symbol '%s' in object '%s'\n",
args.count, name, objname);
pr_err("unresolvable ambiguity for symbol '%s' in object '%s'\n",
name, objname);
} else if (sympos != args.count && sympos > 0) {
pr_err("symbol position %lu for symbol '%s' in object '%s' not found\n",
sympos, name, objname ? objname : "vmlinux");
@ -866,88 +866,49 @@ int klp_register_patch(struct klp_patch *patch)
}
EXPORT_SYMBOL_GPL(klp_register_patch);
static int klp_module_notify_coming(struct klp_patch *patch,
struct klp_object *obj)
{
struct module *pmod = patch->mod;
struct module *mod = obj->mod;
int ret;
ret = klp_init_object_loaded(patch, obj);
if (ret) {
pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n",
pmod->name, mod->name, ret);
return ret;
}
if (patch->state == KLP_DISABLED)
return 0;
pr_notice("applying patch '%s' to loading module '%s'\n",
pmod->name, mod->name);
ret = klp_enable_object(obj);
if (ret)
pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",
pmod->name, mod->name, ret);
return ret;
}
static void klp_module_notify_going(struct klp_patch *patch,
struct klp_object *obj)
{
struct module *pmod = patch->mod;
struct module *mod = obj->mod;
if (patch->state == KLP_DISABLED)
goto disabled;
pr_notice("reverting patch '%s' on unloading module '%s'\n",
pmod->name, mod->name);
klp_disable_object(obj);
disabled:
klp_free_object_loaded(obj);
}
static int klp_module_notify(struct notifier_block *nb, unsigned long action,
void *data)
int klp_module_coming(struct module *mod)
{
int ret;
struct module *mod = data;
struct klp_patch *patch;
struct klp_object *obj;
if (action != MODULE_STATE_COMING && action != MODULE_STATE_GOING)
return 0;
if (WARN_ON(mod->state != MODULE_STATE_COMING))
return -EINVAL;
mutex_lock(&klp_mutex);
/*
* Each module has to know that the notifier has been called.
* We never know what module will get patched by a new patch.
* Each module has to know that klp_module_coming()
* has been called. We never know what module will
* get patched by a new patch.
*/
if (action == MODULE_STATE_COMING)
mod->klp_alive = true;
else /* MODULE_STATE_GOING */
mod->klp_alive = false;
mod->klp_alive = true;
list_for_each_entry(patch, &klp_patches, list) {
klp_for_each_object(patch, obj) {
if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
continue;
if (action == MODULE_STATE_COMING) {
obj->mod = mod;
ret = klp_module_notify_coming(patch, obj);
if (ret) {
obj->mod = NULL;
pr_warn("patch '%s' is in an inconsistent state!\n",
patch->mod->name);
}
} else /* MODULE_STATE_GOING */
klp_module_notify_going(patch, obj);
obj->mod = mod;
ret = klp_init_object_loaded(patch, obj);
if (ret) {
pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n",
patch->mod->name, obj->mod->name, ret);
goto err;
}
if (patch->state == KLP_DISABLED)
break;
pr_notice("applying patch '%s' to loading module '%s'\n",
patch->mod->name, obj->mod->name);
ret = klp_enable_object(obj);
if (ret) {
pr_warn("failed to apply patch '%s' to module '%s' (%d)\n",
patch->mod->name, obj->mod->name, ret);
goto err;
}
break;
}
@ -956,12 +917,56 @@ static int klp_module_notify(struct notifier_block *nb, unsigned long action,
mutex_unlock(&klp_mutex);
return 0;
err:
/*
* If a patch is unsuccessfully applied, return
* error to the module loader.
*/
pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",
patch->mod->name, obj->mod->name, obj->mod->name);
mod->klp_alive = false;
klp_free_object_loaded(obj);
mutex_unlock(&klp_mutex);
return ret;
}
static struct notifier_block klp_module_nb = {
.notifier_call = klp_module_notify,
.priority = INT_MIN+1, /* called late but before ftrace notifier */
};
void klp_module_going(struct module *mod)
{
struct klp_patch *patch;
struct klp_object *obj;
if (WARN_ON(mod->state != MODULE_STATE_GOING &&
mod->state != MODULE_STATE_COMING))
return;
mutex_lock(&klp_mutex);
/*
* Each module has to know that klp_module_going()
* has been called. We never know what module will
* get patched by a new patch.
*/
mod->klp_alive = false;
list_for_each_entry(patch, &klp_patches, list) {
klp_for_each_object(patch, obj) {
if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
continue;
if (patch->state != KLP_DISABLED) {
pr_notice("reverting patch '%s' on unloading module '%s'\n",
patch->mod->name, obj->mod->name);
klp_disable_object(obj);
}
klp_free_object_loaded(obj);
break;
}
}
mutex_unlock(&klp_mutex);
}
static int __init klp_init(void)
{
@ -973,21 +978,11 @@ static int __init klp_init(void)
return -EINVAL;
}
ret = register_module_notifier(&klp_module_nb);
if (ret)
return ret;
klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj);
if (!klp_root_kobj) {
ret = -ENOMEM;
goto unregister;
}
if (!klp_root_kobj)
return -ENOMEM;
return 0;
unregister:
unregister_module_notifier(&klp_module_nb);
return ret;
}
module_init(klp_init);

36
kernel/module.c
View File

@ -53,6 +53,7 @@
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
#include <linux/livepatch.h>
#include <linux/async.h>
#include <linux/percpu.h>
#include <linux/kmemleak.h>
@ -984,6 +985,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
mod->exit();
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
ftrace_release_mod(mod);
async_synchronize_full();
@ -3258,6 +3260,7 @@ fail:
module_put(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
ftrace_release_mod(mod);
free_module(mod);
wake_up_all(&module_wq);
@ -3335,9 +3338,6 @@ static int complete_formation(struct module *mod, struct load_info *info)
mod->state = MODULE_STATE_COMING;
mutex_unlock(&module_mutex);
ftrace_module_enable(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_COMING, mod);
return 0;
out:
@ -3345,6 +3345,20 @@ out:
return err;
}
static int prepare_coming_module(struct module *mod)
{
int err;
ftrace_module_enable(mod);
err = klp_module_coming(mod);
if (err)
return err;
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_COMING, mod);
return 0;
}
static int unknown_module_param_cb(char *param, char *val, const char *modname,
void *arg)
{
@ -3459,13 +3473,17 @@ static int load_module(struct load_info *info, const char __user *uargs,
if (err)
goto ddebug_cleanup;
err = prepare_coming_module(mod);
if (err)
goto bug_cleanup;
/* Module is ready to execute: parsing args may do that. */
after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
-32768, 32767, mod,
unknown_module_param_cb);
if (IS_ERR(after_dashes)) {
err = PTR_ERR(after_dashes);
goto bug_cleanup;
goto coming_cleanup;
} else if (after_dashes) {
pr_warn("%s: parameters '%s' after `--' ignored\n",
mod->name, after_dashes);
@ -3474,7 +3492,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
/* Link in to syfs. */
err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
if (err < 0)
goto bug_cleanup;
goto coming_cleanup;
/* Get rid of temporary copy. */
free_copy(info);
@ -3484,15 +3502,17 @@ static int load_module(struct load_info *info, const char __user *uargs,
return do_init_module(mod);
coming_cleanup:
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
bug_cleanup:
/* module_bug_cleanup needs module_mutex protection */
mutex_lock(&module_mutex);
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
/* we can't deallocate the module until we clear memory protection */
module_disable_ro(mod);
module_disable_nx(mod);