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From:   "Ertman, David M" <david.m.ertman@intel.com>
To:     Ivan Vecera <ivecera@redhat.com>
CC:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        Petr Oros <poros@redhat.com>,
        "Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
        "Nguyen, Anthony L" <anthony.l.nguyen@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "intel-wired-lan@lists.osuosl.org" <intel-wired-lan@lists.osuosl.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH net] ice: Fix race condition during interface enslave
Thread-Topic: [PATCH net] ice: Fix race condition during interface enslave
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Date:   Thu, 10 Mar 2022 19:26:02 +0000
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> -----Original Message-----
> From: Ivan Vecera <ivecera@redhat.com>
> Sent: Thursday, March 10, 2022 10:07 AM
> To: Ertman, David M <david.m.ertman@intel.com>
> Cc: netdev@vger.kernel.org; Petr Oros <poros@redhat.com>; Brandeburg,
> Jesse <jesse.brandeburg@intel.com>; Nguyen, Anthony L
> <anthony.l.nguyen@intel.com>; David S. Miller <davem@davemloft.net>;
> Jakub Kicinski <kuba@kernel.org>; moderated list:INTEL ETHERNET DRIVERS"
> <intel-wired-lan@lists.osuosl.org>, open list <linux-kernel@vger.kernel.o=
rg>
> Subject: Re: [PATCH net] ice: Fix race condition during interface enslave
>=20
> On Thu, 10 Mar 2022 17:48:16 +0000
> "Ertman, David M" <david.m.ertman@intel.com> wrote:
>=20
> > This only addresses one case of unplugging the auxiliary bus.  Rather t=
han
> controlling one instance of
> > calling ice_unplig_aux_dev(), it seems like it would be better to modif=
y
> ice_unplug_aux_dev so that it
> > will pause until any plugging is done by the service task (check for th=
e pf-
> >flag bit and wait until it clears
> > before progressing).
>=20
> You cannot wait in ice_unplug_aux_dev() for ICE_FLAG_PLUG_AUX_DEV to
> be cleared because
> ice_clear_rdma_cap() is called under RTNL.
> This patch is a counter part for commit 5dbbbd01cbba83 ("ice: Avoid RTNL
> lock when
> re-creating auxiliary device") that eliminates ice_plug_aux() and fixed f=
irst
> part
> of deadlock and this patch fixes a second part and eliminates also
> ice_unplug_aux_dev()
> to be called under RTNL.
>=20
> Thanks,
> Ivan

You are correct.  I forgot about the RTNL context!

With this in mind - I agree with your approach.

Reviewed-by: Dave Ertman <david.m.ertman@intel.com>