CVE-2026-31485

Summary

In the Linux kernel, the following vulnerability has been resolved:

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().

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6
• https://git.kernel.org/stable/c/ca4483f36ac1b62e69f8b182c5b8f059e0abecfb
• https://git.kernel.org/stable/c/e3fd54f8b0317fbccc103961ddd660f2a32dcf0b
• https://git.kernel.org/stable/c/adb25339b66112393fd6892ceff926765feb5b86
• https://git.kernel.org/stable/c/d5d01f24bc6fbde40b4e567ef9160194b61267bc
• https://git.kernel.org/stable/c/e89e2b97253c124d37bf88e96e5e8ce5c3aeeec3
• https://git.kernel.org/stable/c/15650dfbaeeb14bcaaf053b93cf631db8d465300
• https://git.kernel.org/stable/c/b341c1176f2e001b3adf0b47154fc31589f7410e

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