From: Dan Carpenter <dan.carpenter@oracle•com>
To: Hillf Danton <hdanton@sina•com>
Cc: syzbot <syzbot+0dc4444774d419e916c8@syzkaller•appspotmail.com>,
airlied@linux•ie, alexander.deucher@amd•com,
amd-gfx@lists•freedesktop.org, chris@chris-wilson•co.uk,
christian.koenig@amd•com, daniel@ffwll•ch, davem@davemloft•net,
dri-devel@lists•freedesktop.org, emil.velikov@collabora•com,
eric@anholt•net, linaro-mm-sig@lists•linaro.org,
linux-kernel@vger•kernel.org, linux-media@vger•kernel.org,
netdev@vger•kernel.org, robdclark@chromium•org,
seanpaul@chromium•org, sumit.semwal@linaro•org,
syzkaller-bugs@googlegroups•com
Subject: Re: KASAN: use-after-free Read in vgem_gem_dumb_create
Date: Sat, 1 Feb 2020 19:25:37 +0300 [thread overview]
Message-ID: <20200201162537.GK1778@kadam> (raw)
In-Reply-To: <20200201090247.10928-1-hdanton@sina.com>
On Sat, Feb 01, 2020 at 05:02:47PM +0800, Hillf Danton wrote:
>
> On Sat, 1 Feb 2020 09:17:57 +0300 Dan Carpenter wrote:
> > On Sat, Feb 01, 2020 at 12:32:09PM +0800, Hillf Danton wrote:
> > >
> > > Release obj in error path.
> > >
> > > --- a/drivers/gpu/drm/vgem/vgem_drv.c
> > > +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> > > @@ -196,10 +196,10 @@ static struct drm_gem_object *vgem_gem_c
> > > return ERR_CAST(obj);
> > >
> > > ret = drm_gem_handle_create(file, &obj->base, handle);
> > > - drm_gem_object_put_unlocked(&obj->base);
> > > - if (ret)
> > > + if (ret) {
> > > + drm_gem_object_put_unlocked(&obj->base);
> > > return ERR_PTR(ret);
> > > -
> > > + }
> > > return &obj->base;
> >
> > Oh yeah. It's weird that we never noticed the success path was broken.
> > It's been that way for three years and no one noticed at all. Very
> > strange.
> >
> > Anyway, it already gets freed on error in drm_gem_handle_create() so
> > we should just delete the drm_gem_object_put_unlocked() here it looks
> > like.
>
> Good catch, Dan :P
> Would you please post a patch sometime convenient next week?
Sure. Will do.
regards,
dan carpenter
next prev parent reply other threads:[~2020-02-01 16:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200201043209.13412-1-hdanton@sina.com>
2020-02-01 6:17 ` KASAN: use-after-free Read in vgem_gem_dumb_create Dan Carpenter
[not found] ` <20200201090247.10928-1-hdanton@sina.com>
2020-02-01 16:25 ` Dan Carpenter [this message]
2020-02-02 13:17 ` Daniel Vetter
2020-01-31 22:28 syzbot
2020-02-01 5:56 ` Dan Carpenter
2020-02-02 4:38 ` syzbot
2020-02-02 13:19 ` Daniel Vetter
2020-02-03 9:06 ` Dan Carpenter
2020-02-03 15:08 ` Christian König
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