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authorLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 21:46:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 21:46:32 -0700
commit0f49fc95b86fc77b867d643e2d38bc9f28035ed4 (patch)
treecdc6297fe95893905d7192df1e7dfb877517eead
parent49dc2b7173010792c6923930ffcee84b7094b7de (diff)
parent7e545d6eca20ce8ef7f66a63146cbff82b2ba760 (diff)
downloadlinux-sh-0f49fc95b86fc77b867d643e2d38bc9f28035ed4.tar.gz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
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
-rw-r--r--MAINTAINERS5
-rw-r--r--arch/s390/include/asm/livepatch.h4
-rw-r--r--arch/x86/include/asm/livepatch.h4
-rw-r--r--include/linux/livepatch.h9
-rw-r--r--kernel/livepatch/core.c151
-rw-r--r--kernel/module.c36
6 files changed, 113 insertions, 96 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index e32f4847e251..94ea42b76b30 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -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
diff --git a/arch/s390/include/asm/livepatch.h b/arch/s390/include/asm/livepatch.h
index a52b6cca873d..d5427c78b1b3 100644
--- a/arch/s390/include/asm/livepatch.h
+++ b/arch/s390/include/asm/livepatch.h
@@ -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
diff --git a/arch/x86/include/asm/livepatch.h b/arch/x86/include/asm/livepatch.h
index e795f5274217..7e68f9558552 100644
--- a/arch/x86/include/asm/livepatch.h
+++ b/arch/x86/include/asm/livepatch.h
@@ -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 */
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index a8828652f794..bd830d590465 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -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_ */
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index bc2c85c064c1..d68fbf63b083 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -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");
@@ -866,103 +866,108 @@ 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)
+int klp_module_coming(struct module *mod)
{
- struct module *pmod = patch->mod;
- struct module *mod = obj->mod;
int ret;
+ struct klp_patch *patch;
+ struct klp_object *obj;
- 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 (WARN_ON(mod->state != MODULE_STATE_COMING))
+ return -EINVAL;
- if (patch->state == KLP_DISABLED)
- return 0;
+ mutex_lock(&klp_mutex);
+ /*
+ * Each module has to know that klp_module_coming()
+ * has been called. We never know what module will
+ * get patched by a new patch.
+ */
+ mod->klp_alive = true;
- pr_notice("applying patch '%s' to loading module '%s'\n",
- pmod->name, mod->name);
+ 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;
- 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;
-}
+ obj->mod = mod;
-static void klp_module_notify_going(struct klp_patch *patch,
- struct klp_object *obj)
-{
- struct module *pmod = patch->mod;
- struct module *mod = obj->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)
- goto disabled;
+ 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;
+ }
+ }
- pr_notice("reverting patch '%s' on unloading module '%s'\n",
- pmod->name, mod->name);
+ mutex_unlock(&klp_mutex);
- klp_disable_object(obj);
+ return 0;
-disabled:
+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 int klp_module_notify(struct notifier_block *nb, unsigned long action,
- void *data)
+void klp_module_going(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_GOING &&
+ mod->state != MODULE_STATE_COMING))
+ return;
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_going()
+ * 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 = 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 (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);
+ 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);
-
- return 0;
}
-static struct notifier_block klp_module_nb = {
- .notifier_call = klp_module_notify,
- .priority = INT_MIN+1, /* called late but before ftrace notifier */
-};
-
static int __init klp_init(void)
{
int ret;
@@ -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);
diff --git a/kernel/module.c b/kernel/module.c
index 87cfeb25cf65..041200ca4a2d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -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);