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From:   Rob Herring <robh+dt@kernel.org>
Date:   Tue, 18 Dec 2018 14:01:32 -0600
Message-ID: <CAL_JsqLjc-tWYOT7ga4oAsgx=rpcWX6_cj80pih-kt=KbFVV=w@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] of: __of_detach_node() - remove node from phandle cache
To:     Frank Rowand <frowand.list@gmail.com>
Cc:     Michael Ellerman <mpe@ellerman.id.au>, mwb@linux.vnet.ibm.com,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
        tlfalcon@linux.vnet.ibm.com, minkim@us.ibm.com,
        devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Tue, Dec 18, 2018 at 12:57 PM Frank Rowand <frowand.list@gmail.com> wrote:
>
> On 12/17/18 2:52 AM, Michael Ellerman wrote:
> > Hi Frank,
> >
> > frowand.list@gmail.com writes:
> >> From: Frank Rowand <frank.rowand@sony.com>
> >>
> >> Non-overlay dynamic devicetree node removal may leave the node in
> >> the phandle cache.  Subsequent calls to of_find_node_by_phandle()
> >> will incorrectly find the stale entry.  Remove the node from the
> >> cache.
> >>
> >> Add paranoia checks in of_find_node_by_phandle() as a second level
> >> of defense (do not return cached node if detached, do not add node
> >> to cache if detached).
> >>
> >> Reported-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
> >> Signed-off-by: Frank Rowand <frank.rowand@sony.com>
> >> ---
> >
> > Similarly here can we add:
> >
> > Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()")
>
> Yes, thanks.
>
>
> > Cc: stable@vger.kernel.org # v4.17+
>
> Nope, 0b3ce78e90fc does not belong in stable (it is a feature, not a bug
> fix).  So the bug will not be in stable.

0b3ce78e90fc landed in v4.17, so Michael's line above is correct.
Annotating it with 4.17 only saves Greg from trying and then emailing
us to backport this patch as it wouldn't apply.

Rob