Description of the problem: After upgrading to kernel 6.8.0-139-generic, the Bluetooth controller fails to initialize. bluetoothctl show reports "No default controller available", and blueman-manager refuses to start with "bluez daemon is not running". bluetoothd itself is running normally — the adapter never completes setup, so the daemon has no controller to expose.
dmesg shows a kernel NULL pointer dereference during hci_power_on, in the MediaTek firmware setup path: [ 8.712121] Bluetooth: hci0: HW/SW Version: 0x008a008a, Build Time: 20250523103438 [ 8.712126] BUG: kernel NULL pointer dereference, address: 0000000000000219 [ 8.712129] #PF: supervisor read access in kernel mode [ 8.712131] #PF: error_code(0x0000) - not-present page [ 8.712137] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 8.712140] CPU: 11 PID: 170 Comm: kworker/u33:0 Tainted: G OE 6.8.0-139-generic #139-Ubuntu [ 8.712144] Hardware name: LENOVO 82WM/LNVNB161216, BIOS LPCN49WW 01/10/2024 [ 8.712146] Workqueue: hci0 hci_power_on [bluetooth] [ 8.712181] RIP: 0010:__pm_runtime_resume+0x1b/0x80 [ 8.712210] Call Trace: [ 8.712216] usb_autopm_get_interface+0x1d/0x60 [ 8.712221] btmtk_usb_hci_wmt_sync+0xa9/0x2e0 [btmtk] [ 8.712229] btmtk_setup_firmware_79xx+0x1c7/0x360 [btmtk] [ 8.712234] btusb_mtk_setup+0x453/0x610 [btusb] [ 8.712242] hci_dev_setup_sync+0x6c/0x430 [bluetooth] [ 8.712276] hci_dev_init_sync+0x3e/0x1c0 [bluetooth] [ 8.712304] hci_dev_open_sync+0xb1/0x350 [bluetooth] [ 8.712334] hci_dev_do_open+0x28/0x70 [bluetooth] [ 8.712359] hci_power_on+0x50/0x210 [bluetooth] The fault occurs in usb_autopm_get_interface(data->intf) called from btmtk_usb_hci_wmt_sync(), suggesting data->intf is not valid at that point in setup. Hardware: Model: Lenovo 82WM (LNVNB161216), BIOS LPCN49WW 01/10/2024 Bluetooth chip: MediaTek MT7922, ASIC revision 79220010, USB ID 0489:e0d8 (Foxconn/Hon Hai) — drivers btusb / btmtk OS: Linux Mint 22 (Ubuntu 24.04 noble base) Regression confirmed: Kernel 6.8.0-138-generic: Works perfectly. Kernel 6.8.0-139-generic: Bluetooth fails completely. Rolling back to 6.8.0-138 immediately restores full Bluetooth functionality. linux-firmware was upgraded in the same transaction (20240318.git3b128b60-0ubuntu2.29 → 0ubuntu3.1), but 6.8.0-138 works correctly with the new firmware installed, isolating the regression to the kernel. Firmware /lib/firmware/mediatek/BT_RAM_CODE_MT7922_1_1_hdr.bin.zst is present. -- 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
