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Message-ID: <d94b5f07-aa37-f4ec-252b-ff1a96b89326@baylibre.com>
Date:   Mon, 5 Jun 2023 15:21:53 +0200
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Subject: Re: [PATCH v2 1/2] ASoC: mediatek: mt8188: fix use-after-free in
 driver remove path
To:     Trevor Wu <trevor.wu@mediatek.com>, broonie@kernel.org,
        lgirdwood@gmail.com, tiwai@suse.com, perex@perex.cz,
        matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com
Cc:     dianders@chromium.org, alsa-devel@alsa-project.org,
        linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20230601033318.10408-1-trevor.wu@mediatek.com>
 <20230601033318.10408-2-trevor.wu@mediatek.com>
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From:   Alexandre Mergnat <amergnat@baylibre.com>
In-Reply-To: <20230601033318.10408-2-trevor.wu@mediatek.com>
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On 01/06/2023 05:33, Trevor Wu wrote:
> During mt8188_afe_init_clock(), mt8188_audsys_clk_register() was called
> followed by several other devm functions. The caller of
> mt8188_afe_init_clock() utilized devm_add_action_or_reset() to call
> mt8188_afe_deinit_clock(). However, the order was incorrect, causing a
> use-after-free issue during remove time.
> 
> At probe time, the order of calls was:
> 1. mt8188_audsys_clk_register
> 2. afe_priv->clk = devm_kcalloc
> 3. afe_priv->clk[i] = devm_clk_get
> 
> At remove time, the order of calls was:
> 1. mt8188_audsys_clk_unregister
> 3. free afe_priv->clk[i]
> 2. free afe_priv->clk
> 
> To resolve the problem, it's necessary to move devm_add_action_or_reset()
> to the appropriate position so that the remove order can be 3->2->1.

Sounds good

Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>

-- 
Regards,
Alexandre