Re: [PATCH v6 5/7] tracing/probes: Use struct_size() instead of defining custom macros

[Masami Hiramatsu <mhiramat@kernel.org>]

On Mon, 16 Aug 2021 23:43:00 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Remove SIZEOF_TRACE_KPROBE() and SIZEOF_TRACE_UPROBE() and use
> struct_size() as that's what it is made for. No need to have custom
> macros. Especially since struct_size() has some extra memory checks for
> correctness.
> 

Good catch!

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you!

> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_kprobe.c | 6 +-----
>  kernel/trace/trace_uprobe.c | 6 +-----
>  2 files changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index ed1e3c2087ab..ca726c9d0859 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -80,10 +80,6 @@ static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
>  	for_each_dyn_event(dpos)		\
>  		if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
>  
> -#define SIZEOF_TRACE_KPROBE(n)				\
> -	(offsetof(struct trace_kprobe, tp.args) +	\
> -	(sizeof(struct probe_arg) * (n)))
> -
>  static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
>  {
>  	return tk->rp.handler != NULL;
> @@ -265,7 +261,7 @@ static struct trace_kprobe *alloc_trace_kprobe(const char *group,
>  	struct trace_kprobe *tk;
>  	int ret = -ENOMEM;
>  
> -	tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
> +	tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL);
>  	if (!tk)
>  		return ERR_PTR(ret);
>  
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 93ff96541971..590bb9a02f8d 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -83,10 +83,6 @@ static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
>  	for_each_dyn_event(dpos)		\
>  		if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
>  
> -#define SIZEOF_TRACE_UPROBE(n)				\
> -	(offsetof(struct trace_uprobe, tp.args) +	\
> -	(sizeof(struct probe_arg) * (n)))
> -
>  static int register_uprobe_event(struct trace_uprobe *tu);
>  static int unregister_uprobe_event(struct trace_uprobe *tu);
>  
> @@ -340,7 +336,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
>  	struct trace_uprobe *tu;
>  	int ret;
>  
> -	tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
> +	tu = kzalloc(struct_size(tu, tp.args, nargs), GFP_KERNEL);
>  	if (!tu)
>  		return ERR_PTR(-ENOMEM);
>  
> -- 
> 2.30.2


-- 
Masami Hiramatsu <mhiramat@kernel.org>