UBUNTU-CVE-2026-98669: Low severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: iio: buffer: serialize buffer teardown with mode claims Buffer-mode claims hold mlock to guarantee that the device remains in buffer mode until the claim is released. Normal buffer updates take infoexistlock followed by mlock in iioupdatebuffers(). However, iiodeviceunregister() disables and deactivates all buffers without taking mlock. This can invalidate buffer state, including activescanmask, while a buffer-mode claim is held. Take mlock in iiodisableallbuffers() so that unregister honors the mode-claim lifetime guarantee. The infoexistlock -> mlock ordering matches iioupdatebuffers().