Re: [PATCH] cutils: fix memory leak in get_relocated_path()

[Stefano Garzarella]

On Tue, Apr 13, 2021 at 12:59:36PM +0200, Philippe Mathieu-Daudé wrote:
> Is this fix aiming at 6.0 release?

The leak is minimal, but the fix is very simple.
So, I think it can go if someone has a pull request to send with other 
patches, but I'm not sure with which tree.

Thanks,
Stefano

> On 4/12/21 7:02 PM, Stefano Garzarella wrote:
> > get_relocated_path() allocates a GString object and returns the
> > character data (C string) to the caller without freeing the memory
> > allocated for that object as reported by valgrind:
> >
> >   24 bytes in 1 blocks are definitely lost in loss record 2,805 of 6,532
> >      at 0x4839809: malloc (vg_replace_malloc.c:307)
> >      by 0x55AABB8: g_malloc (in /usr/lib64/libglib-2.0.so.0.6600.8)
> >      by 0x55C2481: g_slice_alloc (in /usr/lib64/libglib-2.0.so.0.6600.8)
> >      by 0x55C4827: g_string_sized_new (in /usr/lib64/libglib-2.0.so.0.6600.8)
> >      by 0x55C4CEA: g_string_new (in /usr/lib64/libglib-2.0.so.0.6600.8)
> >      by 0x906314: get_relocated_path (cutils.c:1036)
> >      by 0x6E1F77: qemu_read_default_config_file (vl.c:2122)
> >      by 0x6E1F77: qemu_init (vl.c:2687)
> >      by 0x3E3AF8: main (main.c:49)
> >
> > Let's use g_string_free(gstring, false) to free only the GString object
> > and transfer the ownership of the character data to the caller.
> >
> > Fixes: f4f5ed2cbd ("cutils: introduce get_relocated_path")
> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > ---
> >  util/cutils.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/util/cutils.c b/util/cutils.c
> > index ee908486da..c9b91e7535 100644
> > --- a/util/cutils.c
> > +++ b/util/cutils.c
> > @@ -1055,5 +1055,5 @@ char *get_relocated_path(const char *dir)
> >          assert(G_IS_DIR_SEPARATOR(dir[-1]));
> >          g_string_append(result, dir - 1);
> >      }
> > -    return result->str;
> > +    return g_string_free(result, false);
> >  }