Re: [PATCH 4/6] perf kmem: Print gfp flags in human readable string

From: Namhyung Kim
Date: Mon May 11 2015 - 11:28:12 EST


On Mon, May 11, 2015 at 11:41:10AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, May 11, 2015 at 11:35:36AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Tue, Apr 21, 2015 at 01:55:05PM +0900, Namhyung Kim escreveu:
> > > Save libtraceevent output and print it in the header.
> >
> > <SNIP>
> >
> > > +static int parse_gfp_flags(struct perf_evsel *evsel, struct perf_sample *sample,
> > > + unsigned int gfp_flags)
> > > +{
> > > + char *str, *pos;
>
> > > + str = strtok_r(seq.buffer, " ", &pos);
> >
> > builtin-kmem.c:743:427: error: âposâ may be used uninitialized in this
> > function [-Werror=maybe-uninitialized]
> > new->human_readable = strdup(str + 10);
> > ^
> > builtin-kmem.c:716:14: note: âposâ was declared here
> > char *str, *pos;
> > ^
>
> Emphasis on the "may", as according to strtok_r your code is ok, its
> just the compiler that needs to be told that no, it is not being
> accessed uninitialized:
>
> <quote man strtok>
> On the first call to strtok_r(), str should point to the string
> to be parsed, and the value of saveptr is ignored. In subsequent calls,
> str should be NULL, and saveptr should be unchanged since the previous
> call.
> </>
>
> So just setting it to NULL is enough.

Agreed.

Thanks for fixing this,
Namhyung
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