Re: [Qemu-devel] [PATCH 4/4] qcow2: Fix leak of opts in qcow2_open

[Fam Zheng <famz@redhat.com>]

On Wed, 08/27 16:40, Benoît Canet wrote:
> The Wednesday 27 Aug 2014 à 14:02:36 (+0800), Fam Zheng wrote :
> > Not all the error paths release opts, fix it by moving it after the fail
> > label.
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  block/qcow2.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/block/qcow2.c b/block/qcow2.c
> > index f9e045f..b4c4a6e 100644
> > --- a/block/qcow2.c
> > +++ b/block/qcow2.c
> > @@ -535,7 +535,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
> >      unsigned int len, i;
> >      int ret = 0;
> >      QCowHeader header;
> > -    QemuOpts *opts;
> > +    QemuOpts *opts = NULL;
> >      Error *local_err = NULL;
> >      uint64_t ext_end;
> >      uint64_t l1_vm_state_index;
> > @@ -932,7 +932,6 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
> >          error_setg(errp, "Unsupported value '%s' for qcow2 option "
> >                     "'overlap-check'. Allowed are either of the following: "
> >                     "none, constant, cached, all", opt_overlap_check);
> > -        qemu_opts_del(opts);
> >          ret = -EINVAL;
> >          goto fail;
> >      }
> > @@ -946,7 +945,6 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
> >                                overlap_check_template & (1 << i)) << i;
> >      }
> >  
> > -    qemu_opts_del(opts);
> >  
> >      if (s->use_lazy_refcounts && s->qcow_version < 3) {
> >          error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
> > @@ -964,6 +962,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
> 
> 
> >      return ret;
> The code is returning here in this case and the qemu_opts_del is hidden in the fail label.
> Do we need to qemu_opts_del on success just before return like it was done before ?

Yes, good catch.

Thanks,
Fam

> 
> >  
> >   fail:
> > +    qemu_opts_del(opts);
> >      g_free(s->unknown_header_fields);
> >      cleanup_unknown_header_ext(bs);
> >      qcow2_free_snapshots(bs);
> > -- 
> > 2.1.0
> > 
> >