Re: [PATCH] perf jit: memset variable st using the correct size

rnaldo Carvalho de Melo
2016-04-19T13:52:27Z

Em Tue, Apr 19, 2016 at 10:47:41AM -0300, rnaldo Carvalho de Melo escreveu:
> Em Tue, Apr 19, 2016 at 12:07:18AM +0100, Colin King escreveu:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > The current code is memsetting the struct stat variable st with
> > the size of stat (which turns out to be 1 byte) rather than the
> > size of variable sz.
>
> Thanks, applied.

BTW, its a obvious bug, but I'll add this to the changeset log to
enlighten others ;-)

[acme@jouet c]$ cc -pedantic sizeof_function.c -o sizeof_function
sizeof_function.c: In function ‘main’:
sizeof_function.c:8:46: warning: invalid application of ‘sizeof’ to a function type [-Wpointer-arith]
printf("sizeof(stat)=%zd, stat=%p\n", sizeof(stat), stat);
^
[acme@jouet c]$ ./sizeof_function
sizeof(stat)=1, stat=0x40063

As my expectation was for this to return sizeof(void *) :-\

- Arnaldo

> - Arnaldo
>
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> > tools/perf/util/jitdump.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
> > index 52fcef3..86afe96 100644
> > --- a/tools/perf/util/jitdump.c
> > +++ b/tools/perf/util/jitdump.c
> > @@ -412,7 +412,7 @@ static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
> > return -1;
> > }
> > if (stat(filename, &st))
> > - memset(&st, 0, sizeof(stat));
> > + memset(&st, 0, sizeof(st));
> >
> > event->mmap2.header.type = PERF_RECORD_MMAP2;
> > event->mmap2.header.misc = PERF_RECORD_MISC_USER;
> > @@ -500,7 +500,7 @@ static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
> > size++; /* for \0 */
> >
> > if (stat(filename, &st))
> > - memset(&st, 0, sizeof(stat));
> > + memset(&st, 0, sizeof(st));
> >
> > size = PERF_ALIGN(size, sizeof(u64));
> >
> > --
> > 2.7.4