Unbalanced Regulator Disable Vulnerability in Linux Kernel's Tegra XUSB

CVE-2025-38535

What is CVE-2025-38535?

In the Linux kernel, a specific implementation in the Tegra XUSB driver led to an unbalanced regulator disable issue during transitions between USB roles. When switching from USB_ROLE_DEVICE to USB_ROLE_NONE, the code incorrectly assumed the regulator needed to be disabled. If this regulator was designated as always-on, the logic failed to account for its state, resulting in erroneous disable attempts and warnings in the system logs. This issue has been rectified by refining the control logic to ensure that regulator operations are effectively balanced and executed solely during appropriate transitions between hosting roles.

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