Received-SPF: pass (google.com: domain of linux-kernel+bounces-40387-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Date: Fri, 26 Jan 2024 11:58:56 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Vincent Donnefort <vdonnefort@google.com>, linux-kernel@vger.kernel.org,
 linux-trace-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com,
 kernel-team@android.com
Subject: Re: [PATCH] tracing/trigger: Fix to return error if failed to alloc
 snapshot
Message-ID: <20240126115856.2884e889@gandalf.local.home>
In-Reply-To: <170622977792.270660.2789298642759362200.stgit@devnote2>
References: <ZbJ19CF2Zv4d0R_Z@google.com>
	<170622977792.270660.2789298642759362200.stgit@devnote2>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit

On Fri, 26 Jan 2024 09:42:58 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Fix register_snapshot_trigger() to return error code if it failed to
> allocate a snapshot instead of 0 (success). Unless that, it will register
> snapshot trigger without an error.
> 
> Fixes: 0bbe7f719985 ("tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation")
> Cc: stable@vger.kernel.org
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks Masami, I'll apply this.

-- Steve

> ---
>  kernel/trace/trace_events_trigger.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
> index 46439e3bcec4..b33c3861fbbb 100644
> --- a/kernel/trace/trace_events_trigger.c
> +++ b/kernel/trace/trace_events_trigger.c
> @@ -1470,8 +1470,10 @@ register_snapshot_trigger(char *glob,
>  			  struct event_trigger_data *data,
>  			  struct trace_event_file *file)
>  {
> -	if (tracing_alloc_snapshot_instance(file->tr) != 0)
> -		return 0;
> +	int ret = tracing_alloc_snapshot_instance(file->tr);
> +
> +	if (ret < 0)
> +		return ret;
>  
>  	return register_trigger(glob, data, file);
>  }