Also affects a Dell Inspiron 16 5625 (AMD, BIOS 1.22.0), so this is not specific to HP or gaming laptops.
System: Ubuntu 24.04 (noble) kernel packages Chip: MediaTek MT7921 combo card (Wi-Fi via mt7921e works normally) USB ID: Bus 003 Device 002: ID 0489:e0c8 Foxconn / Hon Hai MediaTek MT7921 Bluetooth Kernels tested: 6.8.0-138-generic: Bluetooth works 6.8.0-139-generic: broken 6.8.0-142-generic: still broken, identical Oops On 139 and 142 the controller never initialises; bluetoothctl list returns nothing. dmesg shows: BUG: kernel NULL pointer dereference, address: 0000000000000219 Workqueue: hci0 hci_power_on [bluetooth] RIP: 0010:__pm_runtime_resume+0x1b/0x80 Call Trace: usb_autopm_get_interface+0x1d/0x60 btmtk_usb_hci_wmt_sync+0xa9/0x2e0 [btmtk] btmtk_setup_firmware_79xx+0x1ca/0x360 [btmtk] btusb_mtk_setup+0x453/0x610 [btusb] hci_dev_setup_sync+0x6f/0x430 [bluetooth] After the Oops, "modprobe -r btusb btmtk" hangs in uninterruptible sleep and the system needs a forced power-off. Candidate commits, all listed under the 6.8.0-139 changelog entry (the entry follows 6.8.0-136 directly), and none touched in 140 or 142: Bluetooth: btmtk: add the function to get the fw name Bluetooth: btusb: mediatek: refactor the function btusb_mtk_reset Bluetooth: btmtk: rename btmediatek_data Bluetooth: btmtk: move btusb_mtk_hci_wmt_sync to btmtk.c Bluetooth: btmtk: fix urb->setup_packet leak in error paths The crash is in btmtk_usb_hci_wmt_sync(), the function created by the "move" commit. RDI=0x50 matches &intf->dev with intf NULL, which suggests btmtk_data->intf is never populated: the upstream btusb.c changes that set it up may not have been backported with this partial series. Reverting these five together should restore 6.8.0-138 behaviour. Happy to test a PPA kernel. This affects the noble GA kernel (linux), not only linux-hwe-6.8. Probable duplicates of this bug: #2166544 (MT7921), #2166569 (MT7961), #2166577 (MT7925). ** Tags added: regression-update -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2165873 Title: Bluetooth fails to initialize due to a kernel NULL pointer error To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2165873/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
