• Qian Cai's avatar
    x86: ACPI: fix CPU hotplug deadlock · 696ac2e3
    Qian Cai authored
    Similar to commit 0266d81e ("acpi/processor: Prevent cpu hotplug
    deadlock") except this is for acpi_processor_ffh_cstate_probe():
    
    "The problem is that the work is scheduled on the current CPU from the
    hotplug thread associated with that CPU.
    
    It's not required to invoke these functions via the workqueue because
    the hotplug thread runs on the target CPU already.
    
    Check whether current is a per cpu thread pinned on the target CPU and
    invoke the function directly to avoid the workqueue."
    
     WARNING: possible circular locking dependency detected
     ------------------------------------------------------
     cpuhp/1/15 is trying to acquire lock:
     ffffc90003447a28 ((work_completion)(&wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630
    
     but task is already holding lock:
     ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20
    
     which lock already depends on the new lock.
    
     the existing dependency chain (in reverse order) is:
    
     -> #1 (cpu_hotplug_lock){++++}-{0:0}:
     cpus_read_lock+0x3e/0xc0
     irq_calc_affinity_vectors+0x5f/0x91
     __pci_enable_msix_range+0x10f/0x9a0
     pci_alloc_irq_vectors_affinity+0x13e/0x1f0
     pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208
     pqi_ctrl_init+0x72f/0x1618 [smartpqi]
     pqi_pci_probe.cold.63+0x882/0x892 [smartpqi]
     local_pci_probe+0x7a/0xc0
     work_for_cpu_fn+0x2e/0x50
     process_one_work+0x57e/0xb90
     worker_thread+0x363/0x5b0
     kthread+0x1f4/0x220
     ret_from_fork+0x27/0x50
    
     -> #0 ((work_completion)(&wfc.work)){+.+.}-{0:0}:
     __lock_acquire+0x2244/0x32a0
     lock_acquire+0x1a2/0x680
     __flush_work+0x4e6/0x630
     work_on_cpu+0x114/0x160
     acpi_processor_ffh_cstate_probe+0x129/0x250
     acpi_processor_evaluate_cst+0x4c8/0x580
     acpi_processor_get_power_info+0x86/0x740
     acpi_processor_hotplug+0xc3/0x140
     acpi_soft_cpu_online+0x102/0x1d0
     cpuhp_invoke_callback+0x197/0x1120
     cpuhp_thread_fun+0x252/0x2f0
     smpboot_thread_fn+0x255/0x440
     kthread+0x1f4/0x220
     ret_from_fork+0x27/0x50
    
     other info that might help us debug this:
    
     Chain exists of:
     (work_completion)(&wfc.work) --> cpuhp_state-up --> cpuidle_lock
    
     Possible unsafe locking scenario:
    
     CPU0                    CPU1
     ----                    ----
     lock(cpuidle_lock);
                             lock(cpuhp_state-up);
                             lock(cpuidle_lock);
     lock((work_completion)(&wfc.work));
    
     *** DEADLOCK ***
    
     3 locks held by cpuhp/1/15:
     #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
     #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
     #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20
    
     Call Trace:
     dump_stack+0xa0/0xea
     print_circular_bug.cold.52+0x147/0x14c
     check_noncircular+0x295/0x2d0
     __lock_acquire+0x2244/0x32a0
     lock_acquire+0x1a2/0x680
     __flush_work+0x4e6/0x630
     work_on_cpu+0x114/0x160
     acpi_processor_ffh_cstate_probe+0x129/0x250
     acpi_processor_evaluate_cst+0x4c8/0x580
     acpi_processor_get_power_info+0x86/0x740
     acpi_processor_hotplug+0xc3/0x140
     acpi_soft_cpu_online+0x102/0x1d0
     cpuhp_invoke_callback+0x197/0x1120
     cpuhp_thread_fun+0x252/0x2f0
     smpboot_thread_fn+0x255/0x440
     kthread+0x1f4/0x220
     ret_from_fork+0x27/0x50
    Signed-off-by: default avatarQian Cai <cai@lca.pw>
    Tested-by: default avatarBorislav Petkov <bp@suse.de>
    [ rjw: Subject ]
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    696ac2e3
cstate.c 5.97 KB