From: Ivan Vecera <ivecera@redhat.com>
To: Michal Schmidt <mschmidt@redhat.com>
Cc: netdev@vger.kernel.org, Petr Oros <poros@redhat.com>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Tony Nguyen <anthony.l.nguyen@intel.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Shiraz Saleem <shiraz.saleem@intel.com>,
Dave Ertman <david.m.ertman@intel.com>,
"moderated list:INTEL ETHERNET DRIVERS"
<intel-wired-lan@lists.osuosl.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net] ice: Fix race during aux device (un)plugging
Date: Fri, 15 Apr 2022 17:49:32 +0200 [thread overview]
Message-ID: <20220415174932.6c85d5ab@ceranb> (raw)
In-Reply-To: <CADEbmW3eUAnvn4gvNxqjCMmO333-=OdObGhDXkrTbDwn0YkJDw@mail.gmail.com>
On Fri, 15 Apr 2022 13:12:03 +0200
Michal Schmidt <mschmidt@redhat.com> wrote:
> On Thu, Apr 14, 2022 at 6:39 PM Ivan Vecera <ivecera@redhat.com> wrote:
>
> > Function ice_plug_aux_dev() assigns pf->adev field too early prior
> > aux device initialization and on other side ice_unplug_aux_dev()
> > starts aux device deinit and at the end assigns NULL to pf->adev.
> > This is wrong and can causes a crash when ice_send_event_to_aux()
> > call occurs during these operations because that function depends
> > on non-NULL value of pf->adev and does not assume that aux device
> > is half-initialized or half-destroyed.
> >
> > Modify affected functions so pf->adev field is set after aux device
> > init and prior aux device destroy.
> >
> [...]
>
> > @@ -320,12 +319,14 @@ int ice_plug_aux_dev(struct ice_pf *pf)
> > */
> > void ice_unplug_aux_dev(struct ice_pf *pf)
> > {
> > - if (!pf->adev)
> > + struct auxiliary_device *adev = pf->adev;
> > +
> > + if (!adev)
> > return;
> >
> > - auxiliary_device_delete(pf->adev);
> > - auxiliary_device_uninit(pf->adev);
> > pf->adev = NULL;
> > + auxiliary_device_delete(adev);
> > + auxiliary_device_uninit(adev);
> > }
> >
>
> Hi Ivan,
> What prevents ice_unplug_aux_dev() from running immediately after
> ice_send_event_to_aux() gets past its "if (!pf->adev)" test ?
> Michal
ice_send_event_to_aux() takes aux device lock. ice_unplug_aux_dev()
calls auxiliary_device_delete() that calls device_del(). device_del()
takes device_lock() prior kill_device(). So if ice_send_event_to_aux()
is in progress then device_del() waits for its completion.
Thanks,
Ivan
next prev parent reply other threads:[~2022-04-15 15:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 16:39 [PATCH net] ice: Fix race during aux device (un)plugging Ivan Vecera
[not found] ` <CADEbmW3eUAnvn4gvNxqjCMmO333-=OdObGhDXkrTbDwn0YkJDw@mail.gmail.com>
2022-04-15 15:49 ` Ivan Vecera [this message]
2022-04-15 17:53 ` Ertman, David M
2022-04-20 6:36 ` Leon Romanovsky
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