Re: [PATCH 5/5] tracing/uprobes: Use trace_event_buffer_reserve() helper

[Masami Hiramatsu]

On Mon, 29 Nov 2021 21:39:50 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
> 
> To be consistent with kprobes and eprobes, use
> trace_event_buffer_reserver() and trace_event_buffer_commit(). This will
> ensure that any updates to trace events will also be implemented on uprobe
> events.
> 

Ah, event_trigger_unlock_commit() is the pair commit function. I got it.
Anyway, the pair of trace_event_buffer_reserve() and trace_event_buffer_commit()
should be used.

Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Thank you,

> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> ---
>  kernel/trace/trace_uprobe.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index f5f0039d31e5..177717c4e74a 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -949,8 +949,8 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
>  				struct trace_event_file *trace_file)
>  {
>  	struct uprobe_trace_entry_head *entry;
> +	struct trace_event_buffer fbuffer;
>  	struct trace_buffer *buffer;
> -	struct ring_buffer_event *event;
>  	void *data;
>  	int size, esize;
>  	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
> @@ -965,12 +965,10 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
>  
>  	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
>  	size = esize + tu->tp.size + dsize;
> -	event = trace_event_buffer_lock_reserve(&buffer, trace_file,
> -						call->event.type, size, 0);
> -	if (!event)
> +	entry = trace_event_buffer_reserve(&fbuffer, trace_file, size);
> +	if (!entry)
>  		return;
>  
> -	entry = ring_buffer_event_data(event);
>  	if (is_ret_probe(tu)) {
>  		entry->vaddr[0] = func;
>  		entry->vaddr[1] = instruction_pointer(regs);
> @@ -982,7 +980,7 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
>  
>  	memcpy(data, ucb->buf, tu->tp.size + dsize);
>  
> -	event_trigger_unlock_commit(trace_file, buffer, event, entry, 0);
> +	trace_event_buffer_commit(&fbuffer);
>  }
>  
>  /* uprobe handler */
> -- 
> 2.33.0


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>