ASoC: mediatek: mt8195: fix use-after-free in driver remove path

During mt8195_afe_init_clock(), mt8195_audsys_clk_register() was called
followed by several other devm functions. At mt8195_afe_deinit_clock()
located at mt8195_afe_pcm_dev_remove(), mt8195_audsys_clk_unregister()
was called.

However, there was an issue with the order in which these functions were
called. Specifically, the remove callback of platform_driver was called
before devres released the resource, resulting in a use-after-free issue
during remove time.

At probe time, the order of calls was:
1. mt8195_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. mt8195_audsys_clk_unregister
3. free afe_priv->clk[i]
2. free afe_priv->clk

To resolve the problem, we can utilize devm_add_action_or_reset() in
mt8195_audsys_clk_register() so that the remove order can be changed to
3->2->1.

Fixes: 6746cc858259 ("ASoC: mediatek: mt8195: add platform driver")
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230601033318.10408-3-trevor.wu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/mediatek/mt8195/mt8195-afe-clk.c b/sound/soc/mediatek/mt8195/mt8195-afe-clk.c
index 9ca2cb8..f35318a 100644 (file)
--- a/sound/soc/mediatek/mt8195/mt8195-afe-clk.c
+++ b/sound/soc/mediatek/mt8195/mt8195-afe-clk.c
@@ -410,11 +410,6 @@ int mt8195_afe_init_clock(struct mtk_base_afe *afe)
        return 0;
 }
 
-void mt8195_afe_deinit_clock(struct mtk_base_afe *afe)
-{
-       mt8195_audsys_clk_unregister(afe);
-}
-
 int mt8195_afe_enable_clk(struct mtk_base_afe *afe, struct clk *clk)
 {
        int ret;

diff --git a/sound/soc/mediatek/mt8195/mt8195-afe-clk.h b/sound/soc/mediatek/mt8195/mt8195-afe-clk.h
index 40663e3..a08c0ee 100644 (file)
--- a/sound/soc/mediatek/mt8195/mt8195-afe-clk.h
+++ b/sound/soc/mediatek/mt8195/mt8195-afe-clk.h
@@ -101,7 +101,6 @@ int mt8195_afe_get_mclk_source_clk_id(int sel);
 int mt8195_afe_get_mclk_source_rate(struct mtk_base_afe *afe, int apll);
 int mt8195_afe_get_default_mclk_source_by_rate(int rate);
 int mt8195_afe_init_clock(struct mtk_base_afe *afe);
-void mt8195_afe_deinit_clock(struct mtk_base_afe *afe);
 int mt8195_afe_enable_clk(struct mtk_base_afe *afe, struct clk *clk);
 void mt8195_afe_disable_clk(struct mtk_base_afe *afe, struct clk *clk);
 int mt8195_afe_prepare_clk(struct mtk_base_afe *afe, struct clk *clk);

diff --git a/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c b/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c
index 9e45efe..03dabc0 100644 (file)
--- a/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c
+++ b/sound/soc/mediatek/mt8195/mt8195-afe-pcm.c
@@ -3255,15 +3255,11 @@ err_pm_put:
 
 static void mt8195_afe_pcm_dev_remove(struct platform_device *pdev)
 {
-       struct mtk_base_afe *afe = platform_get_drvdata(pdev);
-
        snd_soc_unregister_component(&pdev->dev);
 
        pm_runtime_disable(&pdev->dev);
        if (!pm_runtime_status_suspended(&pdev->dev))
                mt8195_afe_runtime_suspend(&pdev->dev);
-
-       mt8195_afe_deinit_clock(afe);
 }
 
 static const struct of_device_id mt8195_afe_pcm_dt_match[] = {

diff --git a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c
index e0670e0..38594bc 100644 (file)
--- a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c
+++ b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.c
@@ -148,6 +148,29 @@ static const struct afe_gate aud_clks[CLK_AUD_NR_CLK] = {
        GATE_AUD6(CLK_AUD_GASRC19, "aud_gasrc19", "top_asm_h", 19),
 };
 
+static void mt8195_audsys_clk_unregister(void *data)
+{
+       struct mtk_base_afe *afe = data;
+       struct mt8195_afe_private *afe_priv = afe->platform_priv;
+       struct clk *clk;
+       struct clk_lookup *cl;
+       int i;
+
+       if (!afe_priv)
+               return;
+
+       for (i = 0; i < CLK_AUD_NR_CLK; i++) {
+               cl = afe_priv->lookup[i];
+               if (!cl)
+                       continue;
+
+               clk = cl->clk;
+               clk_unregister_gate(clk);
+
+               clkdev_drop(cl);
+       }
+}
+
 int mt8195_audsys_clk_register(struct mtk_base_afe *afe)
 {
        struct mt8195_afe_private *afe_priv = afe->platform_priv;
@@ -188,27 +211,5 @@ int mt8195_audsys_clk_register(struct mtk_base_afe *afe)
                afe_priv->lookup[i] = cl;
        }
 
-       return 0;
-}
-
-void mt8195_audsys_clk_unregister(struct mtk_base_afe *afe)
-{
-       struct mt8195_afe_private *afe_priv = afe->platform_priv;
-       struct clk *clk;
-       struct clk_lookup *cl;
-       int i;
-
-       if (!afe_priv)
-               return;
-
-       for (i = 0; i < CLK_AUD_NR_CLK; i++) {
-               cl = afe_priv->lookup[i];
-               if (!cl)
-                       continue;
-
-               clk = cl->clk;
-               clk_unregister_gate(clk);
-
-               clkdev_drop(cl);
-       }
+       return devm_add_action_or_reset(afe->dev, mt8195_audsys_clk_unregister, afe);
 }

diff --git a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h
index 239d310..69db2dd 100644 (file)
--- a/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h
+++ b/sound/soc/mediatek/mt8195/mt8195-audsys-clk.h
@@ -10,6 +10,5 @@
 #define _MT8195_AUDSYS_CLK_H_
 
 int mt8195_audsys_clk_register(struct mtk_base_afe *afe);
-void mt8195_audsys_clk_unregister(struct mtk_base_afe *afe);
 
 #endif