Re: [PATCH] rt-utils.c: Fix write() return value check

[John Kacur <jkacur@gmail.com>]

On Thu, 12 Feb 2026, Gabriele Monaco wrote:

> The write() return value check in tracemark() is a copy-paste from the
> one in tracing_stop() which checks for 2 bytes to be written. As a
> result, tracemark() is almost always warning.
> 
> Check for the write() return value to be equal to the written length,
> which is the value returned if no error occurred.
> While at it, add "\n" to the warn messages.
> 
> Fixes: 60d60540c009 ("rt-utils.c: Check return values of write()")
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
> ---
>  src/lib/rt-utils.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/src/lib/rt-utils.c b/src/lib/rt-utils.c
> index d800b5f..aa70c78 100644
> --- a/src/lib/rt-utils.c
> +++ b/src/lib/rt-utils.c
> @@ -437,8 +437,8 @@ void tracemark(char *fmt, ...)
>  
>  	/* write the tracemark message */
>  	ret = write(tracemark_fd, tracebuf, len);
> -	if (ret != 2)
> -		warn("trace stop write failed");
> +	if (ret != len)
> +		warn("trace mark write failed\n");
>  }
>  
>  void tracing_stop(void)
> @@ -449,7 +449,7 @@ void tracing_stop(void)
>  		return;
>  	ret = write(trace_fd, "0\n", 2);
>  	if (ret != 2)
> -		warn("trace stop write failed");
> +		warn("trace stop write failed\n");
>  }
>  
>  void enable_trace_mark(void)
> 
> base-commit: 4e68b52f0e0c9777c91088948374c6ee3d4a1f6b
> -- 

Signed-off-by: John Kacur <jkacur@redhat.com>