Re: [PATCH] trace-cmd: Fix use of uninitialized variable

[Steven Rostedt <rostedt@goodmis.org>]

On Wed,  2 Feb 2022 13:46:46 -0800
Ian Rogers <irogers@google.com> wrote:

> Caught by clang's -Wsometimes-uninitialized and accepting the suggested
> fix:
> 
> lib/trace-cmd/trace-input.c:4325:6: error: variable 'sec' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
>         if (handle->file_state >= start_state) {
>             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/trace-cmd/trace-input.c:4336:6: note: uninitialized use occurs here
>         if (sec)
>             ^~~
> lib/trace-cmd/trace-input.c:4325:2: note: remove the 'if' if its condition is always true
>         if (handle->file_state >= start_state) {
>         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/trace-cmd/trace-input.c:4311:26: note: initialize the variable 'sec' to silence this warning
>         struct file_section *sec;
>                                 ^
>                                  = NULL

-ENOSOB

  ;-)

-- Steve

> ---
>  lib/trace-cmd/trace-input.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index ecb5682..57bd4ee 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -4308,7 +4308,7 @@ int tracecmd_copy_headers(struct tracecmd_input *handle, int fd,
>  			  enum tracecmd_file_states start_state,
>  			  enum tracecmd_file_states end_state)
>  {
> -	struct file_section *sec;
> +	struct file_section *sec = NULL;
>  	int ret;
>  
>  	if (!start_state)