iio: trigger: cancel reenable_work before freeing trigger

Overview

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

iio: trigger: cancel reenable_work before freeing trigger

iio_trigger_notify_done_atomic() defers ->reenable() into trig->reenable_work on the system workqueue, and the worker dereferences the owning trigger through container_of(). Nothing cancels this work before iio_trig_release() frees the trigger, so a worker armed by the last in-flight IRQ can outlive the free and touch freed memory.

Cancel it at the top of iio_trig_release(), which every free path reaches through the device core's final put_device().

Found by an in-house static analysis tool.

Affected

• Linux >= 9020ef659885f2622cfb386cc229b6d618362895 < cf513df1a2c75566cdc802d9da47f62e8d6cfd18
• Linux >= 9020ef659885f2622cfb386cc229b6d618362895 < e64703280ce7a23a43c27efebeb7da457c88bf5c
• Linux >= 9020ef659885f2622cfb386cc229b6d618362895 < 882d0011c59ff8ac15188ec9ce071399ecfa10ad
• Linux >= 9020ef659885f2622cfb386cc229b6d618362895 < 2a57b9246cecd5dd797a42eb310d6c8816f26d9e
• Linux a18aeac73c0f692ba40964f5f56e182312ae843b
• Linux 2c5c948451d57596640b20887b06b523d376eb24
• Linux >= 5.15.17 < 5.16
• Linux >= 5.16.3 < 5.17
• Linux 5.17

Remediation

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