Hi Paul, I see the following splat just booting net-next or bpf-next trees. I have lockdep and kasan on (if that matters). Is this a known issue? [ 3.011826] cblist_init_generic: Setting adjustable number of callback queues. [ 3.011880] [ 3.011883] ============================= [ 3.011885] [ BUG: Invalid wait context ] [ 3.011889] 5.19.0-14019-g75179e2b7f9a #4201 Not tainted [ 3.011893] ----------------------------- [ 3.011896] swapper/0/1 is trying to lock: [ 3.011899] ffffffff85be94b8 (&port_lock_key){....}-{3:3}, at: serial8250_console_write+0x5fc/0x640 [ 3.011929] other info that might help us debug this: [ 3.011931] context-{5:5} [ 3.011934] 3 locks held by swapper/0/1: [ 3.011938] #0: ffffffff8404dae0 (rcu_tasks_rude.cbs_gbl_lock){....}-{2:2}, at: cblist_init_generic+0x27/0x340 [ 3.011964] #1: ffffffff84041d80 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0xda/0x2e0 [ 3.011984] #2: ffffffff839416e0 (console_owner){....}-{0:0}, at: console_emit_next_record.constprop.37+0x1c9/0x4d0 [ 3.012004] stack backtrace: [ 3.012007] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-14019-g75179e2b7f9a #4201 [ 3.012011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [ 3.012011] Call Trace: [ 3.012011] <TASK> [ 3.012011] dump_stack_lvl+0x44/0x57 [ 3.012011] __lock_acquire.cold.73+0xc7/0x31b [ 3.012011] ? lockdep_hardirqs_on_prepare+0x1f0/0x1f0 [ 3.012011] ? rcu_read_lock_sched_held+0x91/0xc0 [ 3.012011] ? rcu_read_lock_bh_held+0xa0/0xa0 [ 3.012011] lock_acquire+0x133/0x380 [ 3.012011] ? serial8250_console_write+0x5fc/0x640 [ 3.012011] ? lock_release+0x3b0/0x3b0 [ 3.012011] _raw_spin_lock_irqsave+0x35/0x50 [ 3.012011] ? serial8250_console_write+0x5fc/0x640 [ 3.012011] serial8250_console_write+0x5fc/0x640 [ 3.012011] ? rcu_read_lock_bh_held+0xa0/0xa0 [ 3.012011] ? serial8250_default_handle_irq+0x80/0x80 [ 3.012011] ? lock_release+0x3b0/0x3b0 [ 3.012011] ? do_raw_spin_lock+0x107/0x1c0 [ 3.012011] ? rwlock_bug.part.2+0x60/0x60 [ 3.012011] ? prb_final_commit+0x50/0x50 [ 3.012011] console_emit_next_record.constprop.37+0x271/0x4d0 [ 3.012011] ? info_print_ext_header.constprop.38+0x110/0x110 [ 3.012011] ? rcu_read_lock_sched_held+0x91/0xc0 [ 3.012011] console_unlock+0x1d8/0x2c0 [ 3.012011] ? devkmsg_open+0x170/0x170 [ 3.012011] ? vprintk_emit+0xda/0x2e0 [ 3.012011] vprintk_emit+0xe3/0x2e0 [ 3.012011] _printk+0x96/0xb0 [ 3.012011] ? pm_suspend.cold.6+0x2e3/0x2e3 [ 3.012011] ? _raw_write_unlock+0x1f/0x30 [ 3.012011] ? do_raw_spin_lock+0x107/0x1c0 [ 3.012011] cblist_init_generic.cold.36+0x24/0x32 [ 3.012011] rcu_init_tasks_generic+0x23/0xf0 [ 3.012011] kernel_init_freeable+0x1d3/0x38a [ 3.012011] ? _raw_spin_unlock_irq+0x24/0x30 [ 3.012011] ? rest_init+0x1d0/0x1d0 [ 3.012011] kernel_init+0x18/0x130 [ 3.012011] ? rest_init+0x1d0/0x1d0 [ 3.012011] ret_from_fork+0x1f/0x30 [ 3.012011] </TASK> [ 3.012029] cblist_init_generic: Setting shift to 3 and lim to 1. [ 3.013301] cblist_init_generic: Setting shift to 3 and lim to 1. [ 3.014203] Running RCU-tasks wait API self tests