linux-kernel - Re: [PATCH] gfs2: Fix error path kobject memory leak

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Date:   Mon, 13 May 2019 20:39:36 +1000
From:   "Tobin C. Harding" <me@...in.cc>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     "Tobin C. Harding" <tobin@...nel.org>,
        Bob Peterson <rpeterso@...hat.com>,
        Andreas Gruenbacher <agruenba@...hat.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>, cluster-devel@...hat.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] gfs2: Fix error path kobject memory leak

On Mon, May 13, 2019 at 09:14:05AM +0200, Greg Kroah-Hartman wrote:
> On Mon, May 13, 2019 at 01:32:13PM +1000, Tobin C. Harding wrote:
> > If a call to kobject_init_and_add() fails we must call kobject_put()
> > otherwise we leak memory.
> > 
> > Function always calls kobject_init_and_add() which always calls
> > kobject_init().
> > 
> > It is safe to leave object destruction up to the kobject release
> > function and never free it manually.
> > 
> > Remove call to kfree() and always call kobject_put() in the error path.
> > 
> > Signed-off-by: Tobin C. Harding <tobin@...nel.org>
> > ---
> > 
> > Is it ok to send patches during the merge window?
> > 
> > Applies on top of Linus' mainline tag: v5.1
> > 
> > Happy to rebase if there are conflicts.
> > 
> > thanks,
> > Tobin.
> > 
> >  fs/gfs2/sys.c | 7 +------
> >  1 file changed, 1 insertion(+), 6 deletions(-)
> > 
> > diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
> > index 1787d295834e..98586b139386 100644
> > --- a/fs/gfs2/sys.c
> > +++ b/fs/gfs2/sys.c
> > @@ -661,8 +661,6 @@ int gfs2_sys_fs_add(struct gfs2_sbd *sdp)
> >  	if (error)
> >  		goto fail_reg;
> >  
> > -	sysfs_frees_sdp = 1; /* Freeing sdp is now done by sysfs calling
> > -				function gfs2_sbd_release. */
> 
> You should also delete this variable at the top of the function, as it
> is now only set once there and never used.

Thanks, I should have gotten a compiler warning for that.  I was feeling
so confident with my builds this morning ... pays not to get too cocky
I suppose.

> With that:
> 
> Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

Thanks, will re-spin.

	Tobin.