Another affected machine: Acer Aspire A515-56, Ubuntu 24.04.4, MediaTek
MT7921 (USB ID 04ca:3802). Same bracket -- 6.8.0-138-generic works,
6.8.0-139-generic dies with the same NULL dereference at 0x219 in
__pm_runtime_resume via btmtk_usb_hci_wmt_sync during btusb_mtk_setup.
Your reading of data->intf being invalid matches what I see. It looks like
the series arrived with the stable patchset tracked by LP: #2160250
("Noble update: upstream stable patchset 2026-07-09"), which backported
"Bluetooth: btmtk: move btusb_mtk_hci_wmt_sync to btmtk.c" and friends
into 6.8. The function does not exist in 6.8.0-138 at all: comparing
Module.symvers of the two installed kernels, btmtk exports
btmtk_usb_hci_wmt_sync and btmtk_fw_get_filename only in -139, and
btmtk.ko grows from 10404 to 13423 bytes.
I have posted the full symbol-level comparison and the firmware-ruled-out
evidence in bug #2166487, together with an apport collection from a broken
boot on MT7921 hardware.
There are now several separate reports of what appears to be one bug:
#2166475, #2166487, #2166497, #2166509, #2166544, #2166561, #2166569,
#2166577, plus #2165873 against linux-hwe-6.8. It would probably help
triage to mark them as duplicates of whichever one the kernel team
prefers to track.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2166475
Title:
[REGRESSION] Bluetooth (btmtk/btusb) non-functional on kernel
6.8.0-139 (works on 6.8.0-138) - ASUS ExpertBook B5602CBA
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2166475/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
