CVE-2025-38535phy: tegra: xusb: Fix unbalanced regulator disable in UTMI PHY mode

Official description

In the Linux kernel, the following vulnerability has been resolved: phy: tegra: xusb: Fix unbalanced regulator disable in UTMI PHY mode When transitioning from USB_ROLE_DEVICE to USB_ROLE_NONE, the code assumed that the regulator should be disabled. However, if the regulator is marked as always-on, regulator_is_enabled() continues to return true, leading to an incorrect attempt to disable a regulator which is not enabled. This can result in warnings such as: [ 250.155624] WARNING: CPU: 1 PID: 7326 at drivers/regulator/core.c:3004 _regulator_disable+0xe4/0x1a0 [ 250.155652] unbalanced disables for VIN_SYS_5V0 To fix this, we move the regulator control logic into tegra186_xusb_padctl_id_override() function since it's directly related to the ID override state. The regulator is now only disabled when the role transitions from USB_ROLE_HOST to USB_ROLE_NONE, by checking the VBUS_ID register. This ensures that regulator enable/disable operations are properly balanced and only occur when actually transitioning to/from host mode.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/ceb645ac6ce052609ee5c8f819a80e8881789b04
• https://git.kernel.org/stable/c/cdcb0ffd6448f6be898956913a42bd08e59fb2ae
• https://git.kernel.org/stable/c/1bb85b5c2bd43b687c3d54eb6328917f90dd38fc
• https://git.kernel.org/stable/c/5367cdeb75cb6c687ca468450bceb2602ab239d8
• https://git.kernel.org/stable/c/ec7f98ff05f0649af0adeb4808c7ba23d6111ef9
• https://git.kernel.org/stable/c/eaa420339658615d26c1cc95cd6cf720b9aebfca
• https://git.kernel.org/stable/c/cefc1caee9dd06c69e2d807edc5949b329f52b22
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
• https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html