spi: ti-qspi: fix use-after-free after DMA setup failure

The driver falls back to PIO mode if DMA setup fails during probe.

Make sure to clear the DMA channel pointer also if buffer allocation fails to avoid passing a pointer to the released channel to the DMA engine (or trying to free the channel a second time on late probe errors or driver unbind).

This issue was flagged by Sashiko when reviewing a devres allocation conversion patch.

---
 drivers/spi/spi-ti-qspi.c | 1 +
 1 file changed, 1 insertion(+)

index 1fbd710d616f..e3b413b9828c 100644
@@ -867,6 +867,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
 		dev_err(qspi->dev,
 			"dma_alloc_coherent failed, using PIO mode\n");
 		dma_release_channel(qspi->rx_chan);
+		qspi->rx_chan = NULL;
 		goto no_dma;
 	}
 	host->dma_rx = qspi->rx_chan;

2.53.0

Applied to

https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-7.1

Thanks!

[1/1] spi: ti-qspi: fix use-after-free after DMA setup failure

      https://git.kernel.org/broonie/spi/c/ea6ec3343e05

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