[PATCH] ASoC: rockchip: i2s: Fix crash on missing pinctrl

[PATCH] ASoC: rockchip: i2s: Fix crash on missing pinctrl

[Chen-Yu Tsai]

From: Chen-Yu Tsai <wens@csie.org>

Commit 44f362c2cc6d ("ASoC: rockchip: i2s: switch BCLK to GPIO") added
pinctrl lookups, but did not skip the lookup if there was no pinctrl
device tied to the I2S controller. As a result, the lookup was done
on an invalid pointer in such cases, causing a kernel panic.

Only do the subsequent pinctrl state lookups and switch if a pinctrl
device was found.

i2s_pinctrl_select_bclk_{on,off} already guard against missing pinctrl
device or pinctrl state, so those two functions aren't touched.

Fixes: 44f362c2cc6d ("ASoC: rockchip: i2s: switch BCLK to GPIO")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---

This is based on next-20220621, which just saw the inclusion of the
commit this patch fixes.

This issue was found and tested on ROC-RK3328-CC. Tried to test on
RK3399, but that has some other DRM driver related crash.

 sound/soc/rockchip/rockchip_i2s.c | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/sound/soc/rockchip/rockchip_i2s.c b/sound/soc/rockchip/rockchip_i2s.c
index be051e48b97b..9fa8ffd712ea 100644
--- a/sound/soc/rockchip/rockchip_i2s.c
+++ b/sound/soc/rockchip/rockchip_i2s.c
@@ -808,24 +808,23 @@ static int rockchip_i2s_probe(struct platform_device *pdev)
 
 	i2s->bclk_ratio = 64;
 	i2s->pinctrl = devm_pinctrl_get(&pdev->dev);
-	if (IS_ERR(i2s->pinctrl))
+	if (IS_ERR(i2s->pinctrl)) {
 		dev_err(&pdev->dev, "failed to find i2s pinctrl\n");
+	} else {
+		i2s->bclk_on = pinctrl_lookup_state(i2s->pinctrl, "bclk_on");
+		if (IS_ERR_OR_NULL(i2s->bclk_on))
+			dev_err(&pdev->dev, "failed to find i2s default state\n");
+		else
+			dev_dbg(&pdev->dev, "find i2s bclk state\n");
 
-	i2s->bclk_on = pinctrl_lookup_state(i2s->pinctrl,
-				   "bclk_on");
-	if (IS_ERR_OR_NULL(i2s->bclk_on))
-		dev_err(&pdev->dev, "failed to find i2s default state\n");
-	else
-		dev_dbg(&pdev->dev, "find i2s bclk state\n");
-
-	i2s->bclk_off = pinctrl_lookup_state(i2s->pinctrl,
-				  "bclk_off");
-	if (IS_ERR_OR_NULL(i2s->bclk_off))
-		dev_err(&pdev->dev, "failed to find i2s gpio state\n");
-	else
-		dev_dbg(&pdev->dev, "find i2s bclk_off state\n");
+		i2s->bclk_off = pinctrl_lookup_state(i2s->pinctrl, "bclk_off");
+		if (IS_ERR_OR_NULL(i2s->bclk_off))
+			dev_err(&pdev->dev, "failed to find i2s gpio state\n");
+		else
+			dev_dbg(&pdev->dev, "find i2s bclk_off state\n");
 
-	i2s_pinctrl_select_bclk_off(i2s);
+		i2s_pinctrl_select_bclk_off(i2s);
+	}
 
 	i2s->playback_dma_data.addr = res->start + I2S_TXDR;
 	i2s->playback_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-- 
2.34.1

Re: [PATCH] ASoC: rockchip: i2s: Fix crash on missing pinctrl

[Mark Brown]

On Wed, 22 Jun 2022 02:57:47 +0800, Chen-Yu Tsai wrote:
> From: Chen-Yu Tsai <wens@csie.org>
> 
> Commit 44f362c2cc6d ("ASoC: rockchip: i2s: switch BCLK to GPIO") added
> pinctrl lookups, but did not skip the lookup if there was no pinctrl
> device tied to the I2S controller. As a result, the lookup was done
> on an invalid pointer in such cases, causing a kernel panic.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: rockchip: i2s: Fix crash on missing pinctrl
      commit: c3b5fd7fbb698496461f280728b456d9927f22af

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark