From b341c1176f2e001b3adf0b47154fc31589f7410e Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Thu, 19 Mar 2026 19:38:12 +0100 Subject: [PATCH] spi: spi-fsl-lpspi: fix teardown order issue (UAF) There is a teardown order issue in the driver. The SPI controller is registered using devm_spi_register_controller(), which delays unregistration of the SPI controller until after the fsl_lpspi_remove() function returns. As the fsl_lpspi_remove() function synchronously tears down the DMA channels, a running SPI transfer triggers the following NULL pointer dereference due to use after free: | fsl_lpspi 42550000.spi: I/O Error in DMA RX | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [...] | Call trace: | fsl_lpspi_dma_transfer+0x260/0x340 [spi_fsl_lpspi] | fsl_lpspi_transfer_one+0x198/0x448 [spi_fsl_lpspi] | spi_transfer_one_message+0x49c/0x7c8 | __spi_pump_transfer_message+0x120/0x420 | __spi_sync+0x2c4/0x520 | spi_sync+0x34/0x60 | spidev_message+0x20c/0x378 [spidev] | spidev_ioctl+0x398/0x750 [spidev] [...] Switch from devm_spi_register_controller() to spi_register_controller() in fsl_lpspi_probe() and add the corresponding spi_unregister_controller() in fsl_lpspi_remove(). Fixes: 5314987de5e5 ("spi: imx: add lpspi bus driver") Signed-off-by: Marc Kleine-Budde Link: https://patch.msgid.link/20260319-spi-fsl-lpspi-fixes-v1-1-b433e435b2d8@pengutronix.de Signed-off-by: Mark Brown --- drivers/spi/spi-fsl-lpspi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c index b361c1bb3e43..45390e9b8cae 100644 --- a/drivers/spi/spi-fsl-lpspi.c +++ b/drivers/spi/spi-fsl-lpspi.c @@ -1009,7 +1009,7 @@ static int fsl_lpspi_probe(struct platform_device *pdev) enable_irq(irq); } - ret = devm_spi_register_controller(&pdev->dev, controller); + ret = spi_register_controller(controller); if (ret < 0) { dev_err_probe(&pdev->dev, ret, "spi_register_controller error\n"); goto free_dma; @@ -1035,6 +1035,7 @@ static void fsl_lpspi_remove(struct platform_device *pdev) struct fsl_lpspi_data *fsl_lpspi = spi_controller_get_devdata(controller); + spi_unregister_controller(controller); fsl_lpspi_dma_exit(controller); pm_runtime_dont_use_autosuspend(fsl_lpspi->dev);