[PATCH v2] ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[PATCH v2] ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[Namit Gupta]

ftrace_module_init happen after dynamic_debug_setup, it is desired that
cleanup should be called after this label however in current implementation
it is called in free module label,ie:even though ftrace in not initialized,
from so many fail case ftrace_release_mod() will be called and unnecessary
traverse the whole list.
In below patch we moved ftrace_release_mod() from free_module label to
ddebug_cleanup label. that is the best possible location, other solution
is to make new label to ftrace_release_mod() but since ftrace_module_init()
is not return with minimum changes it should be in ddebug_cleanup label.


Signed-off-by: Namit Gupta <gupta.namit@samsung.com>

---
 kernel/module.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 0d1cb8d..4be966a 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3523,6 +3523,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	unset_module_core_ro_nx(mod);
 
  ddebug_cleanup:
+	ftrace_release_mod(mod);
 	dynamic_debug_remove(info->debug);
 	synchronize_sched();
 	kfree(mod->args);
@@ -3541,12 +3542,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	synchronize_rcu();
 	mutex_unlock(&module_mutex);
  free_module:
-	/*
-	 * Ftrace needs to clean up what it initialized.
-	 * This does nothing if ftrace_module_init() wasn't called,
-	 * but it must be called outside of module_mutex.
-	 */
-	ftrace_release_mod(mod);
 	/* Free lock-classes; relies on the preceding sync_rcu() */
 	lockdep_free_key_range(mod->module_core, mod->core_size);
 
-- 
1.9.1

RE: [PATCH v2] ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[NAMIT GUPTA]

 
Hello Steve,

As per the discussion I sent patch v2.

Please find.

Thanks,
Namit Gupta


--------- Original Message ---------
Sender : NAMIT GUPTA <gupta.namit@samsung.com> ./Senior Chief Engineer/SRI-Delhi-Platform S/W 1 Team/Samsung Electronics
Date   : 2017-12-12 17:29 (GMT+5:30)
Title  : [PATCH v2] ftrace/module: Move ftrace_release_mod to ddebug_cleanup label
 
ftrace_module_init happen after dynamic_debug_setup, it is desired that
cleanup should be called after this label however in current implementation
it is called in free module label,ie:even though ftrace in not initialized,
from so many fail case ftrace_release_mod() will be called and unnecessary
traverse the whole list.
In below patch we moved ftrace_release_mod() from free_module label to
ddebug_cleanup label. that is the best possible location, other solution
is to make new label to ftrace_release_mod() but since ftrace_module_init()
is not return with minimum changes it should be in ddebug_cleanup label.
 
 
Signed-off-by: Namit Gupta <gupta.namit@samsung.com>
 
---
 kernel/module.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)
 
diff --git a/kernel/module.c b/kernel/module.c
index 0d1cb8d..4be966a 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3523,6 +3523,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
         unset_module_core_ro_nx(mod);
 
  ddebug_cleanup:
+        ftrace_release_mod(mod);
         dynamic_debug_remove(info->debug);
         synchronize_sched();
         kfree(mod->args);
@@ -3541,12 +3542,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
         synchronize_rcu();
         mutex_unlock(&module_mutex);
  free_module:
-        /*
-         * Ftrace needs to clean up what it initialized.
-         * This does nothing if ftrace_module_init() wasn't called,
-         * but it must be called outside of module_mutex.
-         */
-        ftrace_release_mod(mod);
         /* Free lock-classes; relies on the preceding sync_rcu() */
         lockdep_free_key_range(mod->module_core, mod->core_size);
 
-- 
1.9.1
 
 

Re: [PATCH v2] ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[Steven Rostedt]

On Thu, 28 Dec 2017 05:14:19 +0000
NAMIT GUPTA <gupta.namit@samsung.com> wrote:

>  
> Hello Steve,
> 
> As per the discussion I sent patch v2.
> 

Thanks, I missed this due to traveling.

-- Steve

Re: [PATCH v2] ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[Steven Rostedt]

Jessica,

Can you take this patch. You can add:

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Thanks!

-- Steve


On Tue, 12 Dec 2017 17:24:32 +0530
Namit Gupta <gupta.namit@samsung.com> wrote:

> ftrace_module_init happen after dynamic_debug_setup, it is desired that
> cleanup should be called after this label however in current implementation
> it is called in free module label,ie:even though ftrace in not initialized,
> from so many fail case ftrace_release_mod() will be called and unnecessary
> traverse the whole list.
> In below patch we moved ftrace_release_mod() from free_module label to
> ddebug_cleanup label. that is the best possible location, other solution
> is to make new label to ftrace_release_mod() but since ftrace_module_init()
> is not return with minimum changes it should be in ddebug_cleanup label.
> 
> 
> Signed-off-by: Namit Gupta <gupta.namit@samsung.com>
> 
> ---
>  kernel/module.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/kernel/module.c b/kernel/module.c
> index 0d1cb8d..4be966a 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3523,6 +3523,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
>  	unset_module_core_ro_nx(mod);
>  
>   ddebug_cleanup:
> +	ftrace_release_mod(mod);
>  	dynamic_debug_remove(info->debug);
>  	synchronize_sched();
>  	kfree(mod->args);
> @@ -3541,12 +3542,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
>  	synchronize_rcu();
>  	mutex_unlock(&module_mutex);
>   free_module:
> -	/*
> -	 * Ftrace needs to clean up what it initialized.
> -	 * This does nothing if ftrace_module_init() wasn't called,
> -	 * but it must be called outside of module_mutex.
> -	 */
> -	ftrace_release_mod(mod);
>  	/* Free lock-classes; relies on the preceding sync_rcu() */
>  	lockdep_free_key_range(mod->module_core, mod->core_size);
>  

Re: ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[Jessica Yu]

+++ Steven Rostedt [28/12/17 11:32 -0500]:
>
>Jessica,
>
>Can you take this patch. You can add:
>
>Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Sure, thanks Steven.

Namit, your patch does not apply cleanly to modules-next nor
linux-next. It looks like you based your patch on an old tree?
(e.g., we got rid of the module_core and core_size fields a few years
ago...) Could you please rebase your patch on linux-next and resend? 

Thanks,

Jessica

>On Tue, 12 Dec 2017 17:24:32 +0530
>Namit Gupta <gupta.namit@samsung.com> wrote:
>
>> ftrace_module_init happen after dynamic_debug_setup, it is desired that
>> cleanup should be called after this label however in current implementation
>> it is called in free module label,ie:even though ftrace in not initialized,
>> from so many fail case ftrace_release_mod() will be called and unnecessary
>> traverse the whole list.
>> In below patch we moved ftrace_release_mod() from free_module label to
>> ddebug_cleanup label. that is the best possible location, other solution
>> is to make new label to ftrace_release_mod() but since ftrace_module_init()
>> is not return with minimum changes it should be in ddebug_cleanup label.
>>
>>
>> Signed-off-by: Namit Gupta <gupta.namit@samsung.com>
>>
>> ---
>>  kernel/module.c | 7 +------
>>  1 file changed, 1 insertion(+), 6 deletions(-)
>>
>> diff --git a/kernel/module.c b/kernel/module.c
>> index 0d1cb8d..4be966a 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -3523,6 +3523,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
>>  	unset_module_core_ro_nx(mod);
>>
>>   ddebug_cleanup:
>> +	ftrace_release_mod(mod);
>>  	dynamic_debug_remove(info->debug);
>>  	synchronize_sched();
>>  	kfree(mod->args);
>> @@ -3541,12 +3542,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
>>  	synchronize_rcu();
>>  	mutex_unlock(&module_mutex);
>>   free_module:
>> -	/*
>> -	 * Ftrace needs to clean up what it initialized.
>> -	 * This does nothing if ftrace_module_init() wasn't called,
>> -	 * but it must be called outside of module_mutex.
>> -	 */
>> -	ftrace_release_mod(mod);
>>  	/* Free lock-classes; relies on the preceding sync_rcu() */
>>  	lockdep_free_key_range(mod->module_core, mod->core_size);
>>
>

Re: ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[Steven Rostedt]

On Fri, 29 Dec 2017 01:36:48 +0100
Jessica Yu <jeyu@kernel.org> wrote:

> +++ Steven Rostedt [28/12/17 11:32 -0500]:
> >
> >Jessica,
> >
> >Can you take this patch. You can add:
> >
> >Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>  
> 
> Sure, thanks Steven.
> 
> Namit, your patch does not apply cleanly to modules-next nor
> linux-next. It looks like you based your patch on an old tree?
> (e.g., we got rid of the module_core and core_size fields a few years
> ago...) Could you please rebase your patch on linux-next and resend? 

I should probably re-review the rebased patch.

-- Steve

Re: ftrace/module: Move ftrace_release_mod to ddebug_cleanup label

[Jessica Yu]

+++ Steven Rostedt [28/12/17 19:57 -0500]:
>On Fri, 29 Dec 2017 01:36:48 +0100
>Jessica Yu <jeyu@kernel.org> wrote:
>
>> +++ Steven Rostedt [28/12/17 11:32 -0500]:
>> >
>> >Jessica,
>> >
>> >Can you take this patch. You can add:
>> >
>> >Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
>>
>> Sure, thanks Steven.
>>
>> Namit, your patch does not apply cleanly to modules-next nor
>> linux-next. It looks like you based your patch on an old tree?
>> (e.g., we got rid of the module_core and core_size fields a few years
>> ago...) Could you please rebase your patch on linux-next and resend?
>
>I should probably re-review the rebased patch.

Yeah, that'd be much appreciated :-)

Thanks!

Jessica