Re: [PATCH v3 2/5] tracepoint: Support tterating tracepoints in a loading module

[Google]

The subject has a typo, "tterating" -> "iterating".

I'll fix it and import this to probes/for-next.

Thank you,

On Sun, 18 Aug 2024 19:43:07 +0900
"Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> 
> Add for_each_tracepoint_in_module() function to iterate tracepoints in
> a module. This API is needed for handling tracepoints in a loading
> module from tracepoint_module_notifier callback function.
> This also update for_each_module_tracepoint() to pass the module to
> callback function so that it can find module easily.
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> ---
>  Changes in v3:
>   - Newly added.
> ---
>  include/linux/tracepoint.h |   17 +++++++++++++++--
>  kernel/tracepoint.c        |   37 +++++++++++++++++++++++++++++--------
>  2 files changed, 44 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> index 837fcf8ec0d5..93a9f3070b48 100644
> --- a/include/linux/tracepoint.h
> +++ b/include/linux/tracepoint.h
> @@ -64,8 +64,13 @@ struct tp_module {
>  bool trace_module_has_bad_taint(struct module *mod);
>  extern int register_tracepoint_module_notifier(struct notifier_block *nb);
>  extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
> -void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *),
> +void for_each_module_tracepoint(void (*fct)(struct tracepoint *,
> +					struct module *, void *),
>  				void *priv);
> +void for_each_tracepoint_in_module(struct module *,
> +				   void (*fct)(struct tracepoint *,
> +					struct module *, void *),
> +				   void *priv);
>  #else
>  static inline bool trace_module_has_bad_taint(struct module *mod)
>  {
> @@ -82,10 +87,18 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb)
>  	return 0;
>  }
>  static inline
> -void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *),
> +void for_each_module_tracepoint(void (*fct)(struct tracepoint *,
> +					struct module *, void *),
>  				void *priv)
>  {
>  }
> +static inline
> +void for_each_tracepoint_in_module(struct module *mod,
> +				   void (*fct)(struct tracepoint *,
> +					struct module *, void *),
> +				   void *priv)
> +{
> +}
>  #endif /* CONFIG_MODULES */
>  
>  /*
> diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> index bed4aad36d92..8879da16ef4d 100644
> --- a/kernel/tracepoint.c
> +++ b/kernel/tracepoint.c
> @@ -736,24 +736,45 @@ static __init int init_tracepoints(void)
>  }
>  __initcall(init_tracepoints);
>  
> +/**
> + * for_each_tracepoint_in_module - iteration on all tracepoints in a module
> + * @mod: module
> + * @fct: callback
> + * @priv: private data
> + */
> +void for_each_tracepoint_in_module(struct module *mod,
> +				   void (*fct)(struct tracepoint *tp,
> +				    struct module *mod, void *priv),
> +				   void *priv)
> +{
> +	tracepoint_ptr_t *begin, *end, *iter;
> +
> +	lockdep_assert_held(&tracepoint_module_list_mutex);
> +
> +	if (!mod)
> +		return;
> +
> +	begin = mod->tracepoints_ptrs;
> +	end = mod->tracepoints_ptrs + mod->num_tracepoints;
> +
> +	for (iter = begin; iter < end; iter++)
> +		fct(tracepoint_ptr_deref(iter), mod, priv);
> +}
> +
>  /**
>   * for_each_module_tracepoint - iteration on all tracepoints in all modules
>   * @fct: callback
>   * @priv: private data
>   */
> -void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
> +void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp,
> +				 struct module *mod, void *priv),
>  				void *priv)
>  {
>  	struct tp_module *tp_mod;
> -	struct module *mod;
>  
>  	mutex_lock(&tracepoint_module_list_mutex);
> -	list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
> -		mod = tp_mod->mod;
> -		for_each_tracepoint_range(mod->tracepoints_ptrs,
> -			mod->tracepoints_ptrs + mod->num_tracepoints,
> -			fct, priv);
> -	}
> +	list_for_each_entry(tp_mod, &tracepoint_module_list, list)
> +		for_each_tracepoint_in_module(tp_mod->mod, fct, priv);
>  	mutex_unlock(&tracepoint_module_list_mutex);
>  }
>  #endif /* CONFIG_MODULES */
> 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>