From: Daniel Vetter <daniel@ffwll.ch>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: kernel test robot <lkp@intel.com>,
David Airlie <airlied@linux.ie>,
dri-devel <dri-devel@lists.freedesktop.org>,
Hans de Goede <hdegoede@redhat.com>,
Thomas Zimmermann <tzimmermann@suse.de>
Subject: Re: [PATCH] drm/vboxvideo: Unmap iomem on probe-failure and remove
Date: Thu, 19 Nov 2020 20:30:59 +0100 [thread overview]
Message-ID: <CAKMK7uGB5-aDSyA42PVs7_86NEfinftvKWx6AKsLFjoUS-1VGw@mail.gmail.com> (raw)
In-Reply-To: <20201119175131.GI18329@kadam>
On Thu, Nov 19, 2020 at 6:51 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> On Thu, Nov 19, 2020 at 12:35:56PM +0100, Hans de Goede wrote:
> > Hi,
> >
> > On 10/27/20 2:51 PM, Hans de Goede wrote:
> > > Add missing pci_iounmap() calls to properly unmap the memory on
> > > probe-failure and remove.
> > >
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >
> > For some reason the spam-filter used by Red Hat's email system has eaten
> > Daniel Vetter's reply to this, so let me copy and paste that from patchwork:
> >
> > Daniel Vetter wrote:
> >
> > > I think switching over to devm would be really nice. And for pci all
> > > you need to do is use pcim_enable_device and delete all the cleanup
> > > code, and it's all done. Hand rolling device cleanup code really isn't
> > > a great idea and way too error-prone. Plus you're using lots of devm_
> > > already.
> >
> > Good point, so I just checked and the vboxvideo code is already
> > using pcim_enable_device() so it looks like this is a false-positive
> > from the lkp@intel.com bot, and Dan Carpenter missed that pcim_enable_device()
> > makes all subsequent pci-resource acquiring calls behave like devm calls,
> > when he forwarded the report to me.
> >
> > Tl;DR: there is no bug / leak and this patch can be dropped.
> >
> > Is there a place where I can report a bug against the lkp@intel.com bot
> > for this false-positive ?
>
> Ah. Thanks!
>
> This is a Smatch bug. There is a list for that smatch@vger.kernel.org
> but I already remove the pci_iomap() from the list of functions that
> needs to be unwound based on your report.
I guess if smatch sees a pci_enable_device but not pcim_enable_device
on the same device as passed to pci_iomap (and a pile of other pci
functions) then it still must be unwound. Could smatch detect that?
There's a lot of pci drivers not using the managed functions, catching
bugs in these would be good.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2020-11-19 19:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 13:51 [PATCH] drm/vboxvideo: Unmap iomem on probe-failure and remove Hans de Goede
2020-10-27 15:23 ` Daniel Vetter
2020-11-19 11:35 ` Hans de Goede
2020-11-19 17:51 ` Dan Carpenter
2020-11-19 19:30 ` Daniel Vetter [this message]
2020-11-20 7:58 ` Dan Carpenter
2020-11-20 9:39 ` Daniel Vetter
2020-11-20 11:00 ` Dan Carpenter
2020-11-20 14:55 ` Daniel Vetter
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