These are the remaining 3 patches that came from the original ftrace/livepatch
module notifier patchset found here: https://lkml.org/lkml/2016/2/8/1180
Basically, the patchset does a bit of module.c cleanup (patch 1 and 2) in
preparation for the klp_module_{coming,going} calls (patch 3). We decided
to stop relying on the module notifier callchain in favor of hard-coding
the appropriate livepatch function calls that handle coming and going
modules. Hard-coding these calls will guarantee that ftrace and livepatch
exit/initialization routines are called in the correct order without
relying on module notifiers.
The patches should be nearly exactly the same as those from the previous
discussion, except in patch 3 I've added back the #if IS_ENABLED(CONFIG_LIVEPATCH)
guard in livepatch.h, and in patch 2 I decided that it might be safer to
change mod->state with the module mutex held.
Patches based on linux-next.
Previous discussion found here: https://lkml.org/lkml/2016/2/8/1180
Jessica Yu (3):
modules: split part of complete_formation() into prepare_coming_module()
modules: set mod->state to GOING before going notifiers are called
livepatch/module: remove livepatch module notifier
include/linux/livepatch.h | 13 +++++
kernel/livepatch/core.c | 145 ++++++++++++++++++++++------------------------
kernel/module.c | 39 ++++++++++---
3 files changed, 113 insertions(+), 84 deletions(-)
--
2.4.3
Put all actions in complete_formation() that are performed after
module->state is set to MODULE_STATE_COMING into a separate function
prepare_coming_module(). This split prepares for the removal of the
livepatch module notifiers in favor of hard-coding function calls to
klp_module_{coming,going} in the module loader.
The complete_formation -> prepare_coming_module split will also make error
handling easier since we can jump to the appropriate error label to do any
module GOING cleanup after all the COMING-actions have completed.
Signed-off-by: Jessica Yu <[email protected]>
---
kernel/module.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 87cfeb2..1981ae0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3312,6 +3312,14 @@ out_unlocked:
return err;
}
+static int prepare_coming_module(struct module *mod)
+{
+ ftrace_module_enable(mod);
+ blocking_notifier_call_chain(&module_notify_list,
+ MODULE_STATE_COMING, mod);
+ return 0;
+}
+
static int complete_formation(struct module *mod, struct load_info *info)
{
int err;
@@ -3335,9 +3343,6 @@ 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:
@@ -3459,13 +3464,17 @@ 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 +3483,7 @@ 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 +3493,16 @@ 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);
+
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);
--
2.4.3
In load_module(), the going notifiers are called during error handling
when an error occurs after the coming notifiers have already been called.
However, a module's state is still MODULE_STATE_COMING when the going
notifiers are called in the error path. To be consistent, also set
mod->state to MODULE_STATE_GOING before calling the going notifiers.
Signed-off-by: Jessica Yu <[email protected]>
---
kernel/module.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/module.c b/kernel/module.c
index 1981ae0..9e80576 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3494,6 +3494,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
return do_init_module(mod);
coming_cleanup:
+ mutex_lock(&module_mutex);
+ mod->state = MODULE_STATE_GOING;
+ mutex_unlock(&module_mutex);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
--
2.4.3
Remove the livepatch module notifier in favor of directly enabling and
disabling patches to modules in the module loader. Hard-coding the
function calls ensures that ftrace_module_enable() is run before
klp_module_coming() during module load, and that klp_module_going() is
run before ftrace_release_mod() during module unload. This way, ftrace
and livepatch code is run in the correct order during the module
load/unload sequence without dependence on the module notifier call chain.
Signed-off-by: Jessica Yu <[email protected]>
---
include/linux/livepatch.h | 13 +++++
kernel/livepatch/core.c | 145 ++++++++++++++++++++++------------------------
kernel/module.c | 10 ++++
3 files changed, 92 insertions(+), 76 deletions(-)
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index c056797..bd830d5 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -24,6 +24,8 @@
#include <linux/module.h>
#include <linux/ftrace.h>
+#if IS_ENABLED(CONFIG_LIVEPATCH)
+
#include <asm/livepatch.h>
enum klp_state {
@@ -132,4 +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 bc2c85c..e902377 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.
@@ -866,103 +866,106 @@ 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);
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))
+ 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 +976,11 @@ 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 9e80576..3609fbd 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);
@@ -3314,7 +3317,13 @@ out_unlocked:
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;
@@ -3499,6 +3508,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
mutex_unlock(&module_mutex);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
+ klp_module_going(mod);
bug_cleanup:
/* module_bug_cleanup needs module_mutex protection */
--
2.4.3
Jessica Yu <[email protected]> writes:
> These are the remaining 3 patches that came from the original ftrace/livepatch
> module notifier patchset found here: https://lkml.org/lkml/2016/2/8/1180
Please add my Acked-by to the first and third.
Cheers,
Rusty.
> Basically, the patchset does a bit of module.c cleanup (patch 1 and 2) in
> preparation for the klp_module_{coming,going} calls (patch 3). We decided
> to stop relying on the module notifier callchain in favor of hard-coding
> the appropriate livepatch function calls that handle coming and going
> modules. Hard-coding these calls will guarantee that ftrace and livepatch
> exit/initialization routines are called in the correct order without
> relying on module notifiers.
>
> The patches should be nearly exactly the same as those from the previous
> discussion, except in patch 3 I've added back the #if IS_ENABLED(CONFIG_LIVEPATCH)
> guard in livepatch.h, and in patch 2 I decided that it might be safer to
> change mod->state with the module mutex held.
>
> Patches based on linux-next.
>
> Previous discussion found here: https://lkml.org/lkml/2016/2/8/1180
>
> Jessica Yu (3):
> modules: split part of complete_formation() into prepare_coming_module()
> modules: set mod->state to GOING before going notifiers are called
> livepatch/module: remove livepatch module notifier
>
> include/linux/livepatch.h | 13 +++++
> kernel/livepatch/core.c | 145 ++++++++++++++++++++++------------------------
> kernel/module.c | 39 ++++++++++---
> 3 files changed, 113 insertions(+), 84 deletions(-)
>
> --
> 2.4.3
Jessica Yu <[email protected]> writes:
> In load_module(), the going notifiers are called during error handling
> when an error occurs after the coming notifiers have already been called.
> However, a module's state is still MODULE_STATE_COMING when the going
> notifiers are called in the error path. To be consistent, also set
> mod->state to MODULE_STATE_GOING before calling the going notifiers.
>
> Signed-off-by: Jessica Yu <[email protected]>
> ---
> kernel/module.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 1981ae0..9e80576 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3494,6 +3494,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
> return do_init_module(mod);
>
> coming_cleanup:
> + mutex_lock(&module_mutex);
> + mod->state = MODULE_STATE_GOING;
> + mutex_unlock(&module_mutex);
> blocking_notifier_call_chain(&module_notify_list,
> MODULE_STATE_GOING, mod);
Actually, reviewing this patch makes me realize it is wrong.
We rely on the state of the module being MODULE_STATE_COMING here:
static inline int strong_try_module_get(struct module *mod)
{
BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
We will just have to document that the notifier can be called with
a module in MODULE_STATE_COMING if it never succeeded its
initialization.
Sorry for the previously false lead,
Rusty.
+++ Rusty Russell [10/03/16 13:57 +1030]:
>Jessica Yu <[email protected]> writes:
>> In load_module(), the going notifiers are called during error handling
>> when an error occurs after the coming notifiers have already been called.
>> However, a module's state is still MODULE_STATE_COMING when the going
>> notifiers are called in the error path. To be consistent, also set
>> mod->state to MODULE_STATE_GOING before calling the going notifiers.
>>
>> Signed-off-by: Jessica Yu <[email protected]>
>> ---
>> kernel/module.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/kernel/module.c b/kernel/module.c
>> index 1981ae0..9e80576 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -3494,6 +3494,9 @@ static int load_module(struct load_info *info, const char __user *uargs,
>> return do_init_module(mod);
>>
>> coming_cleanup:
>> + mutex_lock(&module_mutex);
>> + mod->state = MODULE_STATE_GOING;
>> + mutex_unlock(&module_mutex);
>> blocking_notifier_call_chain(&module_notify_list,
>> MODULE_STATE_GOING, mod);
>
>Actually, reviewing this patch makes me realize it is wrong.
>
>We rely on the state of the module being MODULE_STATE_COMING here:
>
> static inline int strong_try_module_get(struct module *mod)
> {
> BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
> if (mod && mod->state == MODULE_STATE_COMING)
> return -EBUSY;
>
>We will just have to document that the notifier can be called with
>a module in MODULE_STATE_COMING if it never succeeded its
>initialization.
Ah, thanks for catching that. I think I remember seeing this conditional and
assuming it wouldn't be a problem since GOING modules would fail in
try_module_get() (as it is does not pass the module_is_live() test) and
subsequently strong_try_module_get() would also fail.. But, I think I ought to
review how module states interact before making a change like this, so, please
ignore this patch.
Jessica
On Wed, Mar 09, 2016 at 05:13:55PM -0500, Jessica Yu wrote:
> Put all actions in complete_formation() that are performed after
> module->state is set to MODULE_STATE_COMING into a separate function
> prepare_coming_module(). This split prepares for the removal of the
> livepatch module notifiers in favor of hard-coding function calls to
> klp_module_{coming,going} in the module loader.
>
> The complete_formation -> prepare_coming_module split will also make error
> handling easier since we can jump to the appropriate error label to do any
> module GOING cleanup after all the COMING-actions have completed.
>
> Signed-off-by: Jessica Yu <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
--
Josh
On Wed, Mar 09, 2016 at 05:13:57PM -0500, Jessica Yu wrote:
> Remove the livepatch module notifier in favor of directly enabling and
> disabling patches to modules in the module loader. Hard-coding the
> function calls ensures that ftrace_module_enable() is run before
> klp_module_coming() during module load, and that klp_module_going() is
> run before ftrace_release_mod() during module unload. This way, ftrace
> and livepatch code is run in the correct order during the module
> load/unload sequence without dependence on the module notifier call chain.
>
> Signed-off-by: Jessica Yu <[email protected]>
> ---
> include/linux/livepatch.h | 13 +++++
> kernel/livepatch/core.c | 145 ++++++++++++++++++++++------------------------
> kernel/module.c | 10 ++++
> 3 files changed, 92 insertions(+), 76 deletions(-)
>
> diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
> index c056797..bd830d5 100644
> --- a/include/linux/livepatch.h
> +++ b/include/linux/livepatch.h
> @@ -24,6 +24,8 @@
> #include <linux/module.h>
> #include <linux/ftrace.h>
>
> +#if IS_ENABLED(CONFIG_LIVEPATCH)
> +
> #include <asm/livepatch.h>
>
> enum klp_state {
> @@ -132,4 +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 bc2c85c..e902377 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.
> @@ -866,103 +866,106 @@ 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);
> 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))
> + return;
If we're removing patch 2/3, then mod->state isn't necessarily GOING. I
think the check can probably just be removed altogether.
With that fixed,
Acked-by: Josh Poimboeuf <[email protected]>
--
Josh