The Linux kernel's pinctrl subsystem for the meson amlogic-a4 platform had a deadlock vulnerability (CVE-2026-64521) caused by pinconf_pins_show() holding pctldev->mutex while the platform driver calls pinctrl_find_gpio_range_from_pin(), which attempts to acquire the same mutex again, resulting in a deadlock. The fix replaces the call with pinctrl_find_gpio_range_from_pin_nolock() to avoid the double mutex acquisition. This issue affects multiple linux-hwe-edge kernel versions prior to 7.0.0-28.28 and related builds. The vulnerability was addressed in official Ubuntu kernel updates as part of a broader security update.

The vulnerability could cause a deadlock when accessing the pinconf-pins sysfs node, potentially leading to system hangs or unresponsiveness. There is no indication of privilege escalation or code execution impact. The issue affects system stability and reliability on affected kernel versions.

An official fix is available and included in Ubuntu security updates. Users should update their systems to the patched kernel versions listed in the Ubuntu advisories and reboot to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. No additional mitigation actions are necessary beyond applying the official updates.