Re: [PATCH] Fix application of sizeof to pointer

From: Steven Rostedt <rostedt@goodmis.org>
To: davidcomponentone@gmail.com
Cc: Viktor.Rosendahl@bmw.de, colin.king@canonical.com,
	vulab@iscas.ac.cn, linux-kernel@vger.kernel.org,
	Zeal Robot <zealci@zte.com.cn>
Subject: Re: [PATCH] Fix application of sizeof to pointer
Date: Mon, 11 Oct 2021 23:06:33 -0400	[thread overview]
Message-ID: <20211011230633.262b54a5@oasis.local.home> (raw)
In-Reply-To: <20211012025424.180781-1-davidcomponentone@gmail.com>

On Tue, 12 Oct 2021 10:54:24 +0800
davidcomponentone@gmail.com wrote:

> From: David Yang <davidcomponentone@gmail.com>
> 
> The coccinelle check report:
> "./tools/tracing/latency/latency-collector.c:1541:10-16:
> ERROR: application of sizeof to pointer"
> Using the "strlen" to fix it.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: David Yang <davidcomponentone@gmail.com>
> ---
>  tools/tracing/latency/latency-collector.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/tracing/latency/latency-collector.c b/tools/tracing/latency/latency-collector.c
> index 3a2e6bb781a8..b131007e6c70 100644
> --- a/tools/tracing/latency/latency-collector.c
> +++ b/tools/tracing/latency/latency-collector.c
> @@ -1538,7 +1538,7 @@ static void tracing_loop(void)
>  				mutex_lock(&print_mtx);
>  				check_signals();
>  				write_or_die(fd_stdout, queue_full_warning,
> -					     sizeof(queue_full_warning));
> +					     strlen(queue_full_warning) + 1);

Really, the +1, although would match if queue_full_warning was an
array, but in this use case, there's no reason to pass the nul
character to the write.

-- Steve

>  				mutex_unlock(&print_mtx);
>  			}
>  			modified--;