iio: adc: xilinx-xadc: free IRQ before cancelling the unmask worker on unbind

Overview

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

iio: adc: xilinx-xadc: free IRQ before cancelling the unmask worker on unbind

The ZYNQ XADC alarm IRQ handler queues zynq_unmask_work via schedule_delayed_work(); that work is cleared by a devm callback. Register the devm callback before devm_request_irq() so the devres LIFO teardown frees the IRQ first, ensuring the handler can no longer queue work by the time the workqueue is cleared. Otherwise the handler could re-arm the work and run it after the xadc structure has been freed.

This issue was found by an in-house static analysis tool.

Affected

• Linux >= 2a9685d1a3b7644ca08d8355fc238b43faef7c3e < a29d385ad7b340c952a3935af2b33488db1eb3a6
• Linux >= 2a9685d1a3b7644ca08d8355fc238b43faef7c3e < a5fe2d1b55faba6d00fd87ad491b6cb603046304
• Linux >= 2a9685d1a3b7644ca08d8355fc238b43faef7c3e < 49ea8a359e362bfbb32a647c8eb7962fbb37234e
• Linux >= 2a9685d1a3b7644ca08d8355fc238b43faef7c3e < 0f3f427076240e75ff265e61645627a71ca4918c
• Linux e96eb8853f334f96312968e4f01c5a452db54c00
• Linux >= 5.10.200 < 5.11
• Linux 5.12

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.