[PATCH] spi: s3c64xx: fix NULL-deref on driver unbind

From: Johan Hovold

Date: Fri Apr 10 2026 - 05:52:39 EST


A change moving DMA channel allocation from probe() back to
s3c64xx_spi_prepare_transfer() failed to remove the corresponding
deallocation from remove().

Drop the bogus DMA channel release from remove() to avoid triggering a
NULL-pointer dereference on driver unbind.

This issue was flagged by Sashiko when reviewing a controller
deregistration fix.

Fixes: f52b03c70744 ("spi: s3c64xx: requests spi-dma channel only during data transfer")
Cc: stable@xxxxxxxxxxxxxxx # 6.0
Cc: Adithya K V <adithya.kv@xxxxxxxxxxx>
Link: https://sashiko.dev/#/patchset/20260410081757.503099-1-johan%40kernel.org
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---

Note that this one should be applied on top of the deregistration fixes:

https://lore.kernel.org/lkml/20260410081757.503099-1-johan@xxxxxxxxxx/

to avoid a (trivial) conflict if applied in reverse order.

Johan


drivers/spi/spi-s3c64xx.c | 5 -----
1 file changed, 5 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 95b61264b679..37176e557099 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -1403,11 +1403,6 @@ static void s3c64xx_spi_remove(struct platform_device *pdev)

writel(0, sdd->regs + S3C64XX_SPI_INT_EN);

- if (!is_polling(sdd)) {
- dma_release_channel(sdd->rx_dma.ch);
- dma_release_channel(sdd->tx_dma.ch);
- }
-
pm_runtime_put_noidle(&pdev->dev);
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
--
2.52.0