Re: [PATCH 1/8] tracing: tprobe-events: Fix a memory leak when tprobe with $retval

[Steven Rostedt]

On Wed, 26 Feb 2025 15:18:46 +0900
"Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> 
> Fix a memory leak when a tprobe is defined with $retval. This
> combination is not allowed, but the parse_symbol_and_return() does
> not free the *symbol which should not be used if it returns the error.
> Thus, it leaks the *symbol memory in that error path.
> 
> Fixes: ce51e6153f77 ("tracing: fprobe-event: Fix to check tracepoint event and return")
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

-- Steve

> ---
>  kernel/trace/trace_fprobe.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
> index b8f3c4ba309b..8826f44f69a4 100644
> --- a/kernel/trace/trace_fprobe.c
> +++ b/kernel/trace/trace_fprobe.c
> @@ -1056,6 +1056,8 @@ static int parse_symbol_and_return(int argc, const char *argv[],
>  			if (is_tracepoint) {
>  				trace_probe_log_set_index(i);
>  				trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
> +				kfree(*symbol);
> +				*symbol = NULL;
>  				return -EINVAL;
>  			}
>  			*is_return = true;