Hi Rafael,
does this ring any bells?
5.6-rc1 with tip/master from today, I'm doing some hotplug stressing,
hunting for another issue when I got this:
[ 759.654555] ======================================================
[ 759.654639] WARNING: possible circular locking dependency detected
[ 759.654727] 5.6.0-rc1+ #1 Not tainted
[ 759.654801] ------------------------------------------------------
[ 759.654885] cpuhp/1/14 is trying to acquire lock:
[ 759.654964] ffff8883cc907a40 ((work_completion)(&wfc.work)){+.+.}, at: __flush_work+0x512/0x830
[ 759.655073]
but task is already holding lock:
[ 759.655155] ffffffff83a9da80 (cpuidle_lock){+.+.}, at: cpuidle_pause_and_lock+0x13/0x20
[ 759.655256]
which lock already depends on the new lock.
[ 759.655346]
the existing dependency chain (in reverse order) is:
[ 759.655463]
-> #3 (cpuidle_lock){+.+.}:
[ 759.655608] __mutex_lock+0x136/0x1320
[ 759.655714] cpuidle_pause_and_lock+0x13/0x20
[ 759.655825] acpi_processor_hotplug+0xfc/0x1c0
[ 759.655932] acpi_soft_cpu_online+0x113/0x190
[ 759.656041] cpuhp_invoke_callback+0x19c/0x1500
[ 759.656149] cpuhp_thread_fun+0x375/0x6d0
[ 759.656256] smpboot_thread_fn+0x52f/0x900
[ 759.656362] kthread+0x324/0x420
[ 759.656466] ret_from_fork+0x27/0x50
[ 759.656568]
-> #2 (cpuhp_state-up){+.+.}:
[ 759.656709] cpuhp_thread_fun+0x2f5/0x6d0
[ 759.656815] smpboot_thread_fn+0x52f/0x900
[ 759.656920] kthread+0x324/0x420
[ 759.657023] ret_from_fork+0x27/0x50
[ 759.657125]
-> #1 (cpu_hotplug_lock.rw_sem){++++}:
[ 759.657268] cpus_read_lock+0x43/0xe0
[ 759.657373] alloc_workqueue+0x7e8/0xc40
[ 759.657481] scsi_host_alloc+0xc61/0x1030
[ 759.657589] ata_scsi_add_hosts+0x2e6/0x580
[ 759.657696] ata_host_register+0x356/0x600
[ 759.657803] ahci_init_one+0x150a/0x1c30
[ 759.657910] local_pci_probe+0xe9/0x1a0
[ 759.658015] work_for_cpu_fn+0x51/0xa0
[ 759.658120] process_one_work+0x79b/0x13f0
[ 759.658227] worker_thread+0x54b/0xbd0
[ 759.658331] kthread+0x324/0x420
[ 759.658434] ret_from_fork+0x27/0x50
[ 759.658535]
-> #0 ((work_completion)(&wfc.work)){+.+.}:
[ 759.658683] __lock_acquire+0x2122/0x3ae0
[ 759.658788] lock_acquire+0x132/0x360
[ 759.658892] __flush_work+0x535/0x830
[ 759.658997] work_on_cpu+0xc9/0xf0
[ 759.659102] acpi_processor_ffh_cstate_probe+0x18a/0x3f0
[ 759.659215] acpi_processor_evaluate_cst+0x638/0x8a0
[ 759.659325] acpi_processor_get_power_info+0xb0/0xdc0
[ 759.659434] acpi_processor_hotplug+0x10c/0x1c0
[ 759.659542] acpi_soft_cpu_online+0x113/0x190
[ 759.659649] cpuhp_invoke_callback+0x19c/0x1500
[ 759.659756] cpuhp_thread_fun+0x375/0x6d0
[ 759.659862] smpboot_thread_fn+0x52f/0x900
[ 759.659967] kthread+0x324/0x420
[ 759.660070] ret_from_fork+0x27/0x50
[ 759.660172]
other info that might help us debug this:
[ 759.660344] Chain exists of:
(work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock
[ 759.660562] Possible unsafe locking scenario:
[ 759.660699] CPU0 CPU1
[ 759.660802] ---- ----
[ 759.660905] lock(cpuidle_lock);
[ 759.661006] lock(cpuhp_state-up);
[ 759.661117] lock(cpuidle_lock);
[ 759.661227] lock((work_completion)(&wfc.work));
[ 759.661333]
*** DEADLOCK ***
[ 759.661498] 3 locks held by cpuhp/1/14:
[ 759.661600] #0: ffffffff8369a2f0 (cpu_hotplug_lock.rw_sem){++++}, at: cpuhp_thread_fun+0xac/0x6d0
[ 759.661755] #1: ffffffff8369a4c0 (cpuhp_state-up){+.+.}, at: cpuhp_thread_fun+0xac/0x6d0
[ 759.661907] #2: ffffffff83a9da80 (cpuidle_lock){+.+.}, at: cpuidle_pause_and_lock+0x13/0x20
[ 759.662061]
stack backtrace:
[ 759.662196] CPU: 1 PID: 14 Comm: cpuhp/1 Not tainted 5.6.0-rc1+ #1
[ 759.662308] Hardware name: GIGABYTE MZ01-CE1-00/MZ01-CE1-00, BIOS F02 08/29/2018
[ 759.662452] Call Trace:
[ 759.662559] dump_stack+0x96/0xe0
[ 759.662663] check_noncircular+0x329/0x3f0
[ 759.662770] ? print_circular_bug.isra.41+0x200/0x200
[ 759.662884] ? mark_lock+0xe6/0x11e0
[ 759.662990] ? rcu_read_lock_bh_held+0xa0/0xa0
[ 759.663098] __lock_acquire+0x2122/0x3ae0
[ 759.663208] ? lock_downgrade+0x6c0/0x6c0
[ 759.663314] ? lockdep_hardirqs_on+0x5c0/0x5c0
[ 759.663424] ? ___preempt_schedule_notrace+0x16/0x35
[ 759.663535] lock_acquire+0x132/0x360
[ 759.663640] ? __flush_work+0x512/0x830
[ 759.663748] __flush_work+0x535/0x830
[ 759.663851] ? __flush_work+0x512/0x830
[ 759.663957] ? queue_delayed_work_on+0xb0/0xb0
[ 759.664063] ? mark_lock+0xe6/0x11e0
[ 759.664170] ? mark_held_locks+0xb0/0x110
[ 759.664275] ? queue_work_on+0x7e/0xa0
[ 759.664380] ? lockdep_hardirqs_on+0x388/0x5c0
[ 759.664489] work_on_cpu+0xc9/0xf0
[ 759.664592] ? flush_delayed_work+0xb0/0xb0
[ 759.664698] ? __exit_umh+0x2f0/0x2f0
[ 759.664802] ? acpi_processor_ffh_cstate_probe+0x3f0/0x3f0
[ 759.664915] ? acpi_processor_get_lpi_info+0xdf/0x320
[ 759.665024] acpi_processor_ffh_cstate_probe+0x18a/0x3f0
[ 759.665136] acpi_processor_evaluate_cst+0x638/0x8a0
[ 759.665248] ? mark_held_locks+0xb0/0x110
[ 759.665353] ? acpi_processor_claim_cst_control+0x100/0x100
[ 759.665465] ? quarantine_put+0xc0/0x160
[ 759.665570] ? lockdep_hardirqs_on+0x388/0x5c0
[ 759.665681] ? __kasan_slab_free+0x141/0x180
[ 759.665791] acpi_processor_get_power_info+0xb0/0xdc0
[ 759.665905] acpi_processor_hotplug+0x10c/0x1c0
[ 759.666013] acpi_soft_cpu_online+0x113/0x190
[ 759.666120] ? acpi_processor_start+0x80/0x80
[ 759.666226] ? lockdep_hardirqs_on+0x5c0/0x5c0
[ 759.666335] ? acpi_processor_start+0x80/0x80
[ 759.667805] cpuhp_invoke_callback+0x19c/0x1500
[ 759.667914] ? cpuhp_thread_fun+0xac/0x6d0
[ 759.668022] cpuhp_thread_fun+0x375/0x6d0
[ 759.668126] ? cpuhp_thread_fun+0xac/0x6d0
[ 759.668231] ? __kthread_parkme+0xc3/0x190
[ 759.668336] ? __cpuhp_state_remove_instance+0x4f0/0x4f0
[ 759.668446] ? smpboot_thread_fn+0x9e/0x900
[ 759.668550] smpboot_thread_fn+0x52f/0x900
[ 759.668657] ? smpboot_register_percpu_thread+0x380/0x380
[ 759.668769] ? __kthread_parkme+0xc3/0x190
[ 759.668875] ? smpboot_register_percpu_thread+0x380/0x380
[ 759.668985] kthread+0x324/0x420
[ 759.669087] ? kthread_create_on_node+0xa0/0xa0
[ 759.669195] ret_from_fork+0x27/0x50
[ 759.669386] ACPI: \_PR_.C002: Found 2 idle states
[ 759.676775] smpboot: Booting Node 0 Processor 10 APIC 0x11
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
