Linux Kernel Runtime Power Management Reference Leak Vulnerability in I2C Cadence Driver

A vulnerability has been identified in the Linux kernel's I2C Cadence driver, specifically within the 'cdns_i2c_master_xfer()' function. This function is supposed to manage runtime power management (PM) references correctly by acquiring a reference when the function is entered and releasing it upon exit. However, there is an error path that bypasses the normal exit procedure, leading to a leak of the runtime PM reference. The vulnerability affects the Linux kernel stable tree.

Impact

The vulnerability causes a runtime power management reference leak, which can lead to improper power management and potentially cause increased power consumption or overheating.

Reproduction

The vulnerability can be reproduced by invoking the 'cdns_i2c_master_xfer()' function in a scenario where the function encounters an error and exits directly, without releasing the acquired runtime power management reference. This can be triggered by setting the I2C adapter to slave mode and not returning to idle state, causing the function to exit prematurely.

Remediation

Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. The specific commit that fixes this issue is available in the Linux kernel stable tree.