Re: [Qemu-devel] [Qemu-stable] [PATCH 09/14] blockdev: Plug memory leak in drive_init()

[Benoît Canet]

The Tuesday 27 May 2014 à 18:13:12 (+0200), Markus Armbruster wrote :
> Benoît Canet <address@hidden> writes:
> 
> > The Monday 26 May 2014 à 19:37:10 (+0200), Markus Armbruster wrote :
> >> Introduced in commit f298d07.  Spotted by Coverity.
> >> 
> >> Signed-off-by: Markus Armbruster <address@hidden>
> >> ---
> >>  blockdev.c | 2 ++
> >>  1 file changed, 2 insertions(+)
> >> 
> >> diff --git a/blockdev.c b/blockdev.c
> >> index 6460c70..7ec7d79 100644
> >> --- a/blockdev.c
> >> +++ b/blockdev.c
> >> @@ -941,6 +941,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, 
> >> BlockInterfaceType block_default_type)
> >>  
> >>      /* Actual block device init: Functionality shared with blockdev-add */
> >>      dinfo = blockdev_init(filename, bs_opts, &local_err);
> >> +    bs_opts = NULL;

What is the purpose of this line ? I though it was to avoid double unref.

> >>      if (dinfo == NULL) {
> >>          if (local_err) {
> >>              qerror_report_err(local_err);
> >> @@ -978,6 +979,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, 
> >> BlockInterfaceType block_default_type)
> >>  
> >>  fail:
> >>      qemu_opts_del(legacy_opts);
> >> +    QDECREF(bs_opts);
> >>      return dinfo;
> >>  }
> >>  
> >> -- 
> >> 1.9.3
> >> 
> >> 
> >
> > This commits seems to fix two thing a leak and a double free.
> > Maybe reflecting this on the commit message would make the bs_opts =
> > NULL; clearer.
> 
> I'm blind.  Can you explain the double free to me?