[PATCH] perf tools: Shut up compiler warning

[PATCH] perf tools: Shut up compiler warning

[Arnaldo Carvalho de Melo]

cc1: warnings being treated as errors
util/trace-event-parse.c: In function ‘parse_ftrace_printk’:
util/trace-event-parse.c:289: warning: ‘fmt’ may be used uninitialized in this function

Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/trace-event-parse.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 4b61b49..0b8a01b 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -286,7 +286,7 @@ void parse_ftrace_printk(char *file, unsigned int size __unused)
 	char *line;
 	char *next = NULL;
 	char *addr_str;
-	char *fmt;
+	char *fmt = NULL;
 	int i;
 
 	line = strtok_r(file, "\n", &next);
-- 
1.5.5.1

Re: [PATCH] perf tools: Shut up compiler warning

[Ingo Molnar]

* Arnaldo Carvalho de Melo <acme@redhat.com> wrote:

> cc1: warnings being treated as errors
> util/trace-event-parse.c: In function ‘parse_ftrace_printk’:
> util/trace-event-parse.c:289: warning: ‘fmt’ may be used uninitialized in this function
> 
> Cc: Steven Rostedt <srostedt@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/perf/util/trace-event-parse.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
> index 4b61b49..0b8a01b 100644
> --- a/tools/perf/util/trace-event-parse.c
> +++ b/tools/perf/util/trace-event-parse.c
> @@ -286,7 +286,7 @@ void parse_ftrace_printk(char *file, unsigned int size __unused)
>  	char *line;
>  	char *next = NULL;
>  	char *addr_str;
> -	char *fmt;
> +	char *fmt = NULL;
>  	int i;
>  
>  	line = strtok_r(file, "\n", &next);

Actually, this might be a real bug that GCC pointed out: what makes sure 
that strtok_r() does not return a NULL (no more tokens) and hence fmt 
remains NULL (crashing the rest of the parser)?

	Ingo

Re: [PATCH] perf tools: Shut up compiler warning

[Steven Rostedt]

On Tue, 2009-10-20 at 07:54 +0200, Ingo Molnar wrote:
> * Arnaldo Carvalho de Melo <acme@redhat.com> wrote:
> 
> > cc1: warnings being treated as errors
> > util/trace-event-parse.c: In function ‘parse_ftrace_printk’:
> > util/trace-event-parse.c:289: warning: ‘fmt’ may be used uninitialized in this function
> > 
> > Cc: Steven Rostedt <srostedt@redhat.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Frederic Weisbecker <fweisbec@gmail.com>
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> > ---
> >  tools/perf/util/trace-event-parse.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
> > index 4b61b49..0b8a01b 100644
> > --- a/tools/perf/util/trace-event-parse.c
> > +++ b/tools/perf/util/trace-event-parse.c
> > @@ -286,7 +286,7 @@ void parse_ftrace_printk(char *file, unsigned int size __unused)
> >  	char *line;
> >  	char *next = NULL;
> >  	char *addr_str;
> > -	char *fmt;
> > +	char *fmt = NULL;
> >  	int i;
> >  
> >  	line = strtok_r(file, "\n", &next);
> 
> Actually, this might be a real bug that GCC pointed out: what makes sure 
> that strtok_r() does not return a NULL (no more tokens) and hence fmt 
> remains NULL (crashing the rest of the parser)?

Ug, yeah that's a bug. That was one of the later changes I did at night.
I'll go look at it and see how it should really be.

Thanks,

-- Steve