linux-kernel - Re: [PATCH v2 3/3] of: overlay: do not free changeset when of_overlay

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Date:   Mon, 2 May 2022 19:59:07 -0500
From:   Rob Herring <robh@...nel.org>
To:     frowand.list@...il.com
Cc:     Slawomir Stepien <slawomir.stepien@...ia.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Rob Herring <robh+dt@...nel.org>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        linux-kernel@...r.kernel.org, Slawomir Stepien <sst@...zta.fm>,
        pantelis.antoniou@...sulko.com, devicetree@...r.kernel.org,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH v2 3/3] of: overlay: do not free changeset when
 of_overlay_apply returns error

On Mon, 02 May 2022 13:17:42 -0500, frowand.list@...il.com wrote:
> From: Frank Rowand <frank.rowand@...y.com>
> 
> New unittests for overlay notifiers reveal a memory leak in
> of_overlay_apply() when a notifier returns an error for action
> OF_OVERLAY_POST_APPLY.  The pr_err() message is:
> 
>    OF: ERROR: memory leak, expected refcount 1 instead of 3,
>    of_node_get()/of_node_put() unbalanced - destroy cset entry: attach
>    overlay node /testcase-data/overlay-node/test-bus/test-unittest17
> 
> Change the error path to no longer call free_overlay_changeset(),
> and document that the caller of of_overlay_fdt_apply() may choose
> to remove the overlay.
> 
> Update the unittest that triggered the error to expect the changed
> return values and to call of_overlay_remove().
> 
> Signed-off-by: Frank Rowand <frank.rowand@...y.com>
> ---
> Changes since version 1:
>   - patch 1/1 v1 did not apply on Rob's dt/next branch, rebase on top of
>     5f756a2eaa44 of: overlay: do not break notify on NOTIFY_{OK|STOP}
> 
> Output of the new overlay notifier unittests, as filtered by
> scripts/dtc/of_unittest_expect:
> 
>    ### dt-test ### pass of_unittest_overlay_notify():2825
> ok OF: overlay: overlay changeset pre-apply notifier error -16, target: /testcase-data/overlay-node/test-bus
>    ### dt-test ### pass of_unittest_overlay_notify():2846
>    ### dt-test ### pass of_unittest_overlay_notify():2851
> ok OF: overlay: overlay changeset post-apply notifier error -17, target: /testcase-data/overlay-node/test-bus
>    ### dt-test ### pass of_unittest_overlay_notify():2857
>    ### dt-test ### pass of_unittest_overlay_notify():2862
>    ### dt-test ### pass of_unittest_overlay_notify():2866
>    ### dt-test ### pass of_unittest_overlay_notify():2872
>    ### dt-test ### pass of_unittest_overlay_notify():2875
> ok OF: overlay: overlay changeset pre-remove notifier error -18, target: /testcase-data/overlay-node/test-bus
>    ### dt-test ### pass of_unittest_overlay_notify():2886
>    ### dt-test ### pass of_unittest_overlay_notify():2894
>    ### dt-test ### pass of_unittest_overlay_notify():2898
>    ### dt-test ### pass of_unittest_overlay_notify():2901
> ok OF: overlay: overlay changeset post-remove notifier error -19, target: /testcase-data/overlay-node/test-bus
>    ### dt-test ### pass of_unittest_overlay_notify():2908
>    ### dt-test ### pass of_unittest_overlay_notify():2915
>    ### dt-test ### pass of_unittest_overlay_notify():2920
>    ### dt-test ### pass of_unittest_overlay_notify():2932
> 
> 
>  drivers/of/overlay.c  | 29 ++++++++++++++++++++++++++---
>  drivers/of/unittest.c | 10 ++++++++--
>  2 files changed, 34 insertions(+), 5 deletions(-)
> 

Applied, thanks!