Re: [Qemu-devel] [PULL 13/15] qemu-img: Allow rebase with no input base

From: Peter Maydell <peter.maydell@linaro.org>
To: Kevin Wolf <kwolf@redhat.com>, Max Reitz <mreitz@redhat.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>,
	Qemu-block <qemu-block@nongnu.org>
Subject: Re: [Qemu-devel] [PULL 13/15] qemu-img: Allow rebase with no input base
Date: Mon, 20 May 2019 16:33:03 +0100	[thread overview]
Message-ID: <CAFEAcA8NthV=ZDV3yhb7Jzp-Mt4SZMHOpgYUEmdTconhresEUw@mail.gmail.com> (raw)
In-Reply-To: <20190510161614.23236-14-kwolf@redhat.com>

On Fri, 10 May 2019 at 17:37, Kevin Wolf <kwolf@redhat.com> wrote:
>
> From: Max Reitz <mreitz@redhat.com>
>
> Currently, without -u, you cannot add a backing file to an image when it
> currently has none:
>
> $ qemu-img rebase -b base.qcow2 foo.qcow2
> qemu-img: Could not open old backing file '': The 'file' block driver
> requires a file name
>
> It is really simple to allow this, though (effectively by setting
> old_backing_size to 0), so this patch does just that.
>
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Hi -- Coverity reports some new "resource leak" errors
in the qemu-img.c img_rebase() function:
 * CID 1401415 : Coverity complains that the memory assigned
   to out_real_path gets leaked if we take the immediately
   following "if (local_err) ... goto out" error-exit path.
   This may be another instance of Coverity not understanding
   that the function won't return non-NULL if errp is set.
 * CID 1401416 : leak of the 'options' qdict in this
   error-exit code path. This looks like a real issue (and
   there seem to be other error-exit codepaths earlier in
   the function which leak this too.)

Would somebody like to have a look at these?

thanks
-- PMM