Hi,
I'm not entirely sure who I'm supposed to send this to, so apologies if
I forgot somebody.
I've had an issue when rebooting on and off for a couple of monthes, but
I got a stacktrace from lockdep today:
[71721.872904] reboot: Restarting system
[71721.876743] ------------[ cut here ]------------
[71721.877081]
[71721.877084] ======================================================
[71721.877086] WARNING: possible circular locking dependency detected
[71721.877088] 5.17.0-rc6-next-20220303-v8+ #10 Not tainted
[71721.877092] ------------------------------------------------------
[71721.877094] swapper/1/0 is trying to acquire lock:
[71721.877097] ffffffc009610900 (console_owner){-.-.}-{0:0}, at: console_unlock+0x194/0x4e0
[71721.877117]
[71721.877117] but task is already holding lock:
[71721.877118] ffffff80fb7974d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x30/0x50
[71721.877131]
[71721.877131] which lock already depends on the new lock.
[71721.877131]
[71721.877132]
[71721.877132] the existing dependency chain (in reverse order) is:
[71721.877133]
[71721.877133] -> #4 (&rq->__lock){-.-.}-{2:2}:
[71721.877139] __lock_acquire+0x458/0xab0
[71721.877146] lock_acquire.part.0+0x9c/0x1e0
[71721.877152] lock_acquire+0x68/0x84
[71721.877157] _raw_spin_lock_nested+0x6c/0x84
[71721.877164] raw_spin_rq_lock_nested+0x30/0x50
[71721.877169] task_fork_fair+0x48/0x164
[71721.877175] sched_cgroup_fork+0xd4/0x130
[71721.877181] copy_process+0xd88/0x1380
[71721.877188] kernel_clone+0x98/0x364
[71721.877193] kernel_thread+0x78/0xb0
[71721.877198] rest_init+0x38/0x2c0
[71721.877202] arch_call_rest_init+0x1c/0x28
[71721.877207] start_kernel+0x644/0x684
[71721.877211] __primary_switched+0xa4/0xac
[71721.877214]
[71721.877214] -> #3 (&p->pi_lock){-.-.}-{2:2}:
[71721.877220] __lock_acquire+0x458/0xab0
[71721.877225] lock_acquire.part.0+0x9c/0x1e0
[71721.877230] lock_acquire+0x68/0x84
[71721.877234] _raw_spin_lock_irqsave+0x90/0xd0
[71721.877241] try_to_wake_up+0x60/0x460
[71721.877247] default_wake_function+0x28/0x50
[71721.877253] woken_wake_function+0x2c/0x40
[71721.877257] __wake_up_common+0xa0/0x180
[71721.877261] __wake_up_common_lock+0x80/0xd0
[71721.877265] __wake_up+0x24/0x30
[71721.877268] tty_wakeup+0x40/0x80
[71721.877274] tty_port_default_wakeup+0x2c/0x4c
[71721.877278] tty_port_tty_wakeup+0x24/0x30
[71721.877282] uart_write_wakeup+0x24/0x34
[71721.877288] serial8250_tx_chars+0x110/0x250
[71721.877293] serial8250_handle_irq.part.0+0x11c/0x170
[71721.877297] serial8250_default_handle_irq+0x58/0x9c
[71721.877301] serial8250_interrupt+0x5c/0xc0
[71721.877305] __handle_irq_event_percpu+0x9c/0x1b4
[71721.877310] handle_irq_event+0x58/0x130
[71721.877314] handle_fasteoi_irq+0xb0/0x1f0
[71721.877321] generic_handle_domain_irq+0x48/0x6c
[71721.877325] gic_handle_irq+0x88/0xc0
[71721.877329] call_on_irq_stack+0x2c/0x58
[71721.877334] do_interrupt_handler+0x88/0xa0
[71721.877339] el1_interrupt+0x34/0x50
[71721.877342] el1h_64_irq_handler+0x18/0x24
[71721.877346] el1h_64_irq+0x64/0x68
[71721.877349] arch_cpu_idle+0x18/0x2c
[71721.877353] default_idle_call+0x6c/0x104
[71721.877358] cpuidle_idle_call+0x158/0x190
[71721.877362] do_idle+0xdc/0x114
[71721.877365] cpu_startup_entry+0x34/0xa0
[71721.877369] rest_init+0x1bc/0x2c0
[71721.877373] arch_call_rest_init+0x1c/0x28
[71721.877376] start_kernel+0x644/0x684
[71721.877379] __primary_switched+0xa4/0xac
[71721.877383]
[71721.877383] -> #2 (&tty->write_wait){-.-.}-{2:2}:
[71721.877389] __lock_acquire+0x458/0xab0
[71721.877393] lock_acquire.part.0+0x9c/0x1e0
[71721.877398] lock_acquire+0x68/0x84
[71721.877403] _raw_spin_lock_irqsave+0x90/0xd0
[71721.877408] __wake_up_common_lock+0x60/0xd0
[71721.877412] __wake_up+0x24/0x30
[71721.877416] tty_wakeup+0x40/0x80
[71721.877421] tty_port_default_wakeup+0x2c/0x4c
[71721.877425] tty_port_tty_wakeup+0x24/0x30
[71721.877428] uart_write_wakeup+0x24/0x34
[71721.877433] serial8250_tx_chars+0x110/0x250
[71721.877438] serial8250_handle_irq.part.0+0x11c/0x170
[71721.877442] serial8250_default_handle_irq+0x58/0x9c
[71721.877446] serial8250_interrupt+0x5c/0xc0
[71721.877450] __handle_irq_event_percpu+0x9c/0x1b4
[71721.877454] handle_irq_event+0x58/0x130
[71721.877459] handle_fasteoi_irq+0xb0/0x1f0
[71721.877464] generic_handle_domain_irq+0x48/0x6c
[71721.877468] gic_handle_irq+0x88/0xc0
[71721.877472] call_on_irq_stack+0x2c/0x58
[71721.877476] do_interrupt_handler+0x88/0xa0
[71721.877481] el1_interrupt+0x34/0x50
[71721.877484] el1h_64_irq_handler+0x18/0x24
[71721.877487] el1h_64_irq+0x64/0x68
[71721.877491] arch_cpu_idle+0x18/0x2c
[71721.877494] default_idle_call+0x6c/0x104
[71721.877499] cpuidle_idle_call+0x158/0x190
[71721.877503] do_idle+0xdc/0x114
[71721.877507] cpu_startup_entry+0x34/0xa0
[71721.877510] rest_init+0x1bc/0x2c0
[71721.877514] arch_call_rest_init+0x1c/0x28
[71721.877518] start_kernel+0x644/0x684
[71721.877521] __primary_switched+0xa4/0xac
[71721.877524]
[71721.877524] -> #1 (&port_lock_key){-.-.}-{2:2}:
[71721.877529] __lock_acquire+0x458/0xab0
[71721.877534] lock_acquire.part.0+0x9c/0x1e0
[71721.877539] lock_acquire+0x68/0x84
[71721.877543] _raw_spin_lock_irqsave+0x90/0xd0
[71721.877549] serial8250_console_write+0x1b4/0x3a0
[71721.877554] univ8250_console_write+0x30/0x40
[71721.877557] call_console_drivers.constprop.0+0x100/0x1fc
[71721.877561] console_unlock+0x1ec/0x4e0
[71721.877564] register_console+0x13c/0x2b0
[71721.877567] uart_add_one_port+0x33c/0x370
[71721.877573] serial8250_register_8250_port+0x328/0x420
[71721.877576] bcm2835aux_serial_probe+0x1c0/0x290
[71721.877585] platform_probe+0x74/0xf0
[71721.877591] really_probe.part.0+0xa4/0x300
[71721.877596] __driver_probe_device+0xa0/0x150
[71721.877600] driver_probe_device+0xb4/0x150
[71721.877604] __driver_attach+0x110/0x1b0
[71721.877608] bus_for_each_dev+0x7c/0xe0
[71721.877612] driver_attach+0x30/0x3c
[71721.877616] bus_add_driver+0x15c/0x200
[71721.877620] driver_register+0x84/0x140
[71721.877624] __platform_driver_register+0x34/0x40
[71721.877630] bcm2835aux_serial_driver_init+0x28/0x34
[71721.877634] do_one_initcall+0x54/0x1a0
[71721.877638] kernel_init_freeable+0x1dc/0x25c
[71721.877642] kernel_init+0x30/0x140
[71721.877645] ret_from_fork+0x10/0x20
[71721.877649]
[71721.877649] -> #0 (console_owner){-.-.}-{0:0}:
[71721.877654] check_prev_add+0xac/0xbcc
[71721.877659] validate_chain+0x420/0x5d0
[71721.877664] __lock_acquire+0x458/0xab0
[71721.877668] lock_acquire.part.0+0x9c/0x1e0
[71721.877673] lock_acquire+0x68/0x84
[71721.877678] console_unlock+0x1dc/0x4e0
[71721.877681] vprintk_emit+0x1c8/0x1ec
[71721.877684] vprintk_default+0x44/0x50
[71721.877688] vprintk+0xc4/0x110
[71721.877691] _printk+0x68/0x90
[71721.877697] report_bug+0x104/0x130
[71721.877704] bug_handler+0x2c/0x80
[71721.877707] call_break_hook+0x70/0x84
[71721.877711] brk_handler+0x28/0x70
[71721.877714] do_debug_exception+0xa4/0x130
[71721.877721] el1_dbg+0x70/0x8c
[71721.877724] el1h_64_sync_handler+0x94/0xd0
[71721.877728] el1h_64_sync+0x64/0x68
[71721.877731] set_task_cpu+0x1b4/0x1f0
[71721.877736] detach_tasks+0x148/0x380
[71721.877741] load_balance+0x240/0x750
[71721.877746] rebalance_domains+0x3c0/0x4d0
[71721.877751] _nohz_idle_balance.constprop.0.isra.0+0x1ec/0x380
[71721.877757] run_rebalance_domains+0x70/0x80
[71721.877762] __do_softirq+0x1a0/0x37c
[71721.877765] __irq_exit_rcu+0x120/0x160
[71721.877770] irq_exit_rcu+0x1c/0x44
[71721.877774] el1_interrupt+0x38/0x50
[71721.877777] el1h_64_irq_handler+0x18/0x24
[71721.877780] el1h_64_irq+0x64/0x68
[71721.877783] arch_cpu_idle+0x18/0x2c
[71721.877787] default_idle_call+0x6c/0x104
[71721.877792] cpuidle_idle_call+0x158/0x190
[71721.877796] do_idle+0xdc/0x114
[71721.877799] cpu_startup_entry+0x30/0xa0
[71721.877803] secondary_start_kernel+0xdc/0x100
[71721.877809] __secondary_switched+0xa0/0xa4
[71721.877814]
[71721.877814] other info that might help us debug this:
[71721.877814]
[71721.877815] Chain exists of:
[71721.877815] console_owner --> &p->pi_lock --> &rq->__lock
[71721.877815]
[71721.877821] Possible unsafe locking scenario:
[71721.877821]
[71721.877823] CPU0 CPU1
[71721.877824] ---- ----
[71721.877825] lock(&rq->__lock);
[71721.877827] lock(&p->pi_lock);
[71721.877830] lock(&rq->__lock);
[71721.877832] lock(console_owner);
[71721.877835]
[71721.877835] *** DEADLOCK ***
[71721.877835]
[71721.877836] 3 locks held by swapper/1/0:
[71721.877839] #0: ffffffc009681fe8 (rcu_read_lock){....}-{1:2}, at: rebalance_domains+0x8c/0x4d0
[71721.877850] #1: ffffff80fb7974d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x30/0x50
[71721.877861] #2: ffffffc009610790 (console_lock){+.+.}-{0:0}, at: console_trylock_spinning+0x20/0x1a4
[71721.877870]
[71721.877870] stack backtrace:
[71721.877872] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc6-next-20220303-v8+ #10
[71721.877877] Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT)
[71721.877880] Call trace:
[71721.877881] dump_backtrace.part.0+0xd4/0xe0
[71721.877884] show_stack+0x24/0x80
[71721.877888] dump_stack_lvl+0x8c/0xb8
[71721.877893] dump_stack+0x18/0x34
[71721.877896] print_circular_bug+0x1f8/0x200
[71721.877901] check_noncircular+0x130/0x144
[71721.877906] check_prev_add+0xac/0xbcc
[71721.877910] validate_chain+0x420/0x5d0
[71721.877915] __lock_acquire+0x458/0xab0
[71721.877920] lock_acquire.part.0+0x9c/0x1e0
[71721.877924] lock_acquire+0x68/0x84
[71721.877929] console_unlock+0x1dc/0x4e0
[71721.877932] vprintk_emit+0x1c8/0x1ec
[71721.877936] vprintk_default+0x44/0x50
[71721.877939] vprintk+0xc4/0x110
[71721.877943] _printk+0x68/0x90
[71721.877948] report_bug+0x104/0x130
[71721.877953] bug_handler+0x2c/0x80
[71721.877956] call_break_hook+0x70/0x84
[71721.877960] brk_handler+0x28/0x70
[71721.877964] do_debug_exception+0xa4/0x130
[71721.877970] el1_dbg+0x70/0x8c
[71721.877973] el1h_64_sync_handler+0x94/0xd0
[71721.877976] el1h_64_sync+0x64/0x68
[71721.877980] set_task_cpu+0x1b4/0x1f0
[71721.877985] detach_tasks+0x148/0x380
[71721.877990] load_balance+0x240/0x750
[71721.877995] rebalance_domains+0x3c0/0x4d0
[71721.878000] _nohz_idle_balance.constprop.0.isra.0+0x1ec/0x380
[71721.878006] run_rebalance_domains+0x70/0x80
[71721.878011] __do_softirq+0x1a0/0x37c
[71721.878014] __irq_exit_rcu+0x120/0x160
[71721.878018] irq_exit_rcu+0x1c/0x44
[71721.878022] el1_interrupt+0x38/0x50
[71721.878026] el1h_64_irq_handler+0x18/0x24
[71721.878029] el1h_64_irq+0x64/0x68
[71721.878032] arch_cpu_idle+0x18/0x2c
[71721.878035] default_idle_call+0x6c/0x104
[71721.878041] cpuidle_idle_call+0x158/0x190
[71721.878045] do_idle+0xdc/0x114
[71721.878048] cpu_startup_entry+0x30/0xa0
[71721.878052] secondary_start_kernel+0xdc/0x100
[71721.878057] __secondary_switched+0xa0/0xa4
[71722.926930] WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:3052 set_task_cpu+0x1b4/0x1f0
[71722.935049] Modules linked in:
[71722.938139] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc6-next-20220303-v8+ #10
[71722.946164] Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT)
[71722.950095] SMP: failed to stop secondary CPUs 0-1
The board would then require a power cycle to boot again (the changes
were some registers changes in KMS, nothing that would affect this part
of the code)
I'm not entirely sure how to fix it. Some versions seems to be more
affected than others. next-20220303 seems to trigger it 100% of the
time, some older versions would reboot fine. Like I said, it's been on
and off, so I think the source has been there for some time, whether it
works or not depends probably on subtle timings or something like that.
Maxime
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