In the Linux kernel, the following vulnerability has been resolved: idpf: fix read_dev_clk_lock spinlock init in idpf_ptp_init() In idpf_ptp_init(), read_dev_clk_lock is initialized after ptp_schedule_worker() had already been called (and after idpf_ptp_settime64() could reach the lock). The PTP aux worker fires immediately upon scheduling and can call into idpf_ptp_read_src_clk_reg_direct(), which takes spin_lock(&ptp->read_dev_clk_lock) on an uninitialized lock, triggering the lockdep "non-static key" warning: [12973.796587] idpf 0000:83:00.0: Device HW Reset initiated [12974.094507] INFO: trying to register non-static key. ... [12974.097208] Call Trace: [12974.097213] <TASK> [12974.097218] dump_stack_lvl+0x93/0xe0 [12974.097234] register_lock_class+0x4c4/0x4e0 [12974.097249] ? __lock_acquire+0x427/0x2290 [12974.097259] __lock_acquire+0x98/0x2290 [12974.097272] lock_acquire+0xc6/0x310 [12974.097281] ? idpf_ptp_read_src_clk_reg+0xb7/0x150 [idpf] [12974.097311] ? lockdep_hardirqs_on_prepare+0xde/0x190 [12974.097318] ? finish_task_switch.isra.0+0xd2/0x350 [12974.097330] ? __pfx_ptp_aux_kworker+0x10/0x10 [ptp] [12974.097343] _raw_spin_lock+0x30/0x40 [12974.097353] ? idpf_ptp_read_src_clk_reg+0xb7/0x150 [idpf] [12974.097373] idpf_ptp_read_src_clk_reg+0xb7/0x150 [idpf] [12974.097391] ? kthread_worker_fn+0x88/0x3d0 [12974.097404] ? kthread_worker_fn+0x4e/0x3d0 [12974.097411] idpf_ptp_update_cached_phctime+0x26/0x120 [idpf] [12974.097428] ? _raw_spin_unlock_irq+0x28/0x50 [12974.097436] idpf_ptp_do_aux_work+0x15/0x20 [idpf] [12974.097454] ptp_aux_kworker+0x20/0x40 [ptp] [12974.097464] kthread_worker_fn+0xd5/0x3d0 [12974.097474] ? __pfx_kthread_worker_fn+0x10/0x10 [12974.097482] kthread+0xf4/0x130 [12974.097489] ? __pfx_kthread+0x10/0x10 [12974.097498] ret_from_fork+0x32c/0x410 [12974.097512] ? __pfx_kthread+0x10/0x10 [12974.097519] ret_from_fork_asm+0x1a/0x30 [12974.097540] </TASK> Move the call to spin_lock_init() up a bit to make sure read_dev_clk_lock is not touched before it's been initialized.