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vmd: Use lock save/restore in interrupt enable path
Enabling interrupts may result in an interrupt raised and serviced while VMD holds a lock, resulting in contention with the spin lock held while enabling interrupts. The solution is to disable preemption and save/restore the state during interrupt enable and disable. Fixes lockdep: [ 52.340274] ====================================================== [ 52.347381] [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ] [ 52.355129] 4.6.0-2016-06-16-lockdep+ torvalds#47 Tainted: G E [ 52.362334] ------------------------------------------------------ [ 52.369443] kworker/0:1/447 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: [ 52.377245] (list_lock){+.+...}, at: [<ffffffffa04eb8fc>] vmd_irq_enable+0x3c/0x70 [vmd] [ 52.386736] [ 52.386736] and this task is already holding: [ 52.393427] (&irq_desc_lock_class){-.-...}, at: [<ffffffff810e1ff6>] __setup_irq+0xa6/0x610 [ 52.403204] which would create a new lock dependency: [ 52.409004] (&irq_desc_lock_class){-.-...} -> (list_lock){+.+...} [ 52.416265] [ 52.416265] but this new dependency connects a HARDIRQ-irq-safe lock: [ 52.425328] (&irq_desc_lock_class){-.-...} ... which became HARDIRQ-irq-safe at: [ 52.434084] [<ffffffff810c9f21>] __lock_acquire+0x981/0xe00 [ 52.440702] [<ffffffff810cb039>] lock_acquire+0x119/0x220 [ 52.447109] [<ffffffff8167294d>] _raw_spin_lock+0x3d/0x80 [ 52.453519] [<ffffffff810e36d4>] handle_level_irq+0x24/0x110 [ 52.460232] [<ffffffff8101f20a>] handle_irq+0x1a/0x30 [ 52.466248] [<ffffffff81675fc1>] do_IRQ+0x61/0x120 [ 52.471966] [<ffffffff8167404c>] ret_from_intr+0x0/0x20 [ 52.478180] [<ffffffff81672e30>] _raw_spin_unlock_irqrestore+0x40/0x60 [ 52.485893] [<ffffffff810e21ee>] __setup_irq+0x29e/0x610 [ 52.492210] [<ffffffff810e25a1>] setup_irq+0x41/0x90 [ 52.498133] [<ffffffff81f5777f>] setup_default_timer_irq+0x1e/0x20 [ 52.505450] [<ffffffff81f57798>] hpet_time_init+0x17/0x19 [ 52.511870] [<ffffffff81f5775a>] x86_late_time_init+0xa/0x11 [ 52.518587] [<ffffffff81f51e9b>] start_kernel+0x382/0x436 [ 52.525006] [<ffffffff81f51308>] x86_64_start_reservations+0x2a/0x2c [ 52.532548] [<ffffffff81f51445>] x86_64_start_kernel+0x13b/0x14a [ 52.539669] [ 52.539669] to a HARDIRQ-irq-unsafe lock: [ 52.545955] (list_lock){+.+...} ... which became HARDIRQ-irq-unsafe at: [ 52.553801] ... [<ffffffff810c9d8e>] __lock_acquire+0x7ee/0xe00 [ 52.560732] [<ffffffff810cb039>] lock_acquire+0x119/0x220 [ 52.567147] [<ffffffff8167294d>] _raw_spin_lock+0x3d/0x80 [ 52.573556] [<ffffffffa04eba42>] vmd_msi_init+0x72/0x150 [vmd] [ 52.580465] [<ffffffff810e8597>] msi_domain_alloc+0xb7/0x140 [ 52.587182] [<ffffffff810e6b10>] irq_domain_alloc_irqs_recursive+0x40/0xa0 [ 52.595295] [<ffffffff810e6cea>] __irq_domain_alloc_irqs+0x14a/0x330 [ 52.602815] [<ffffffff810e8a8c>] msi_domain_alloc_irqs+0x8c/0x1d0 [ 52.616372] [<ffffffff813ca4e3>] pci_msi_setup_msi_irqs+0x43/0x70 [ 52.629967] [<ffffffff813cada1>] pci_enable_msi_range+0x131/0x280 [ 52.643533] [<ffffffff813bf5e0>] pcie_port_device_register+0x320/0x4e0 [ 52.657800] [<ffffffff813bf9a4>] pcie_portdrv_probe+0x34/0x60 [ 52.670985] [<ffffffff813b0e85>] local_pci_probe+0x45/0xa0 [ 52.683782] [<ffffffff813b226b>] pci_device_probe+0xdb/0x130 [ 52.696720] [<ffffffff8149e3cc>] driver_probe_device+0x22c/0x440 [ 52.710053] [<ffffffff8149e774>] __device_attach_driver+0x94/0x110 [ 52.723578] [<ffffffff8149bfad>] bus_for_each_drv+0x5d/0x90 [ 52.736258] [<ffffffff8149e030>] __device_attach+0xc0/0x140 [ 52.748793] [<ffffffff8149e0c0>] device_attach+0x10/0x20 [ 52.760936] [<ffffffff813a77f7>] pci_bus_add_device+0x47/0x90 [ 52.773563] [<ffffffff813a7879>] pci_bus_add_devices+0x39/0x70 [ 52.786176] [<ffffffff813aaba7>] pci_rescan_bus+0x27/0x30 [ 52.798099] [<ffffffffa04ec1af>] vmd_probe+0x68f/0x76c [vmd] [ 52.810302] [<ffffffff813b0e85>] local_pci_probe+0x45/0xa0 [ 52.822584] [<ffffffff81088064>] work_for_cpu_fn+0x14/0x20 [ 52.834688] [<ffffffff8108c244>] process_one_work+0x1f4/0x740 [ 52.846834] [<ffffffff8108c9c6>] worker_thread+0x236/0x4f0 [ 52.858896] [<ffffffff810935c2>] kthread+0xf2/0x110 [ 52.869910] [<ffffffff816738f2>] ret_from_fork+0x22/0x50 [ 52.881391] [ 52.881391] other info that might help us debug this: [ 52.881391] [ 52.906283] Possible interrupt unsafe locking scenario: [ 52.906283] [ 52.924922] CPU0 CPU1 [ 52.935372] ---- ---- [ 52.945702] lock(list_lock); [ 52.954329] local_irq_disable(); [ 52.966240] lock(&irq_desc_lock_class); [ 52.978859] lock(list_lock); [ 52.990325] <Interrupt> [ 52.998369] lock(&irq_desc_lock_class); [ 53.008269] [ 53.008269] *** DEADLOCK *** Acked-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
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