On Fri, Oct 21, 2016 at 08:14:43AM -0400, Prarit Bhargava wrote: > The following unhandled IRQ warning is seen during shutdown: > > irq 16: nobody cared (try booting with the "irqpoll" option) > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.2-1.el7_UNSUPPORTED.x86_64 #1 > Hardware name: Hewlett-Packard HP Z820 Workstation/158B, BIOS J63 v03.90 06/01/2016 > 0000000000000000 ffff88041f803e70 ffffffff81333bd5 ffff88041cb78200 > ffff88041cb7829c ffff88041f803e98 ffffffff810d9465 ffff88041cb78200 > 0000000000000000 0000000000000028 ffff88041f803ed0 ffffffff810d97bf > Call Trace: > <IRQ> [<ffffffff81333bd5>] dump_stack+0x63/0x8e > [<ffffffff810d9465>] __report_bad_irq+0x35/0xd0 > [<ffffffff810d97bf>] note_interrupt+0x20f/0x260 > [<ffffffff810d6b35>] handle_irq_event_percpu+0x45/0x60 > [<ffffffff810d6b7c>] handle_irq_event+0x2c/0x50 > [<ffffffff810da31a>] handle_fasteoi_irq+0x8a/0x150 > [<ffffffff8102edfb>] handle_irq+0xab/0x130 > [<ffffffff81082391>] ? _local_bh_enable+0x21/0x50 > [<ffffffff817064ad>] do_IRQ+0x4d/0xd0 > [<ffffffff81704502>] common_interrupt+0x82/0x82 > <EOI> [<ffffffff815d0181>] ? cpuidle_enter_state+0xc1/0x280 > [<ffffffff815d0174>] ? cpuidle_enter_state+0xb4/0x280 > [<ffffffff815d0377>] cpuidle_enter+0x17/0x20 > [<ffffffff810bf660>] cpu_startup_entry+0x220/0x3a0 > [<ffffffff816f6da7>] rest_init+0x77/0x80 > [<ffffffff81d8e147>] start_kernel+0x495/0x4a2 > [<ffffffff81d8daa0>] ? set_init_arg+0x55/0x55 > [<ffffffff81d8d120>] ? early_idt_handler_array+0x120/0x120 > [<ffffffff81d8d5d6>] x86_64_start_reservations+0x2a/0x2c > [<ffffffff81d8d715>] x86_64_start_kernel+0x13d/0x14c > > pci_device_shutdown() is called on each PCI device, and does > > if (drv && drv->shutdown) > drv->shutdown(pci_dev); > pci_msi_shutdown(pci_dev); > pci_msix_shutdown(pci_dev); > > The pci_msi_shutdown() and pci_msix_shutdown() functions both call > pci_intx_for_msi() which enables the intx interrupt independent of the driver. > The driver still thinks it is using MSI/X and the result is the above stack > trace. > > We have seen this at Red Hat on various drivers: nouveau, ahci, and pcieport > (so far). Google search for "unhandled irq 16" yields many results reporting > similar behavior during shutdown indicating that this problem is widespread. I've occasionally seen this on an Ivy Bridge MacBook Pro as well, also on IRQ 16. It's been a major annoyance, so thanks for looking into this. Why is this always occurring on IRQ 16, not on any others? On my MacBook Pro IRQ 16 is used by a root port (00:1c.0, pcieport), an Ethernet controller below that root port (02:00.0, tg3) and a Thunderbolt hotplug bridge (06:03.0, pcieport). I've never seen these spurious interrupts on any other IRQ. The patch looks good, I'm wondering though if it works correctly with PCI devices passed through to a VM: When the VM is shut down, it won't enable INTx any longer. Not sure if this can cause problems for the host. Thanks, Lukas > I can cause this to happen on a "stable" system by adding a 3 second delay in > pci_device_shutdown() which causes the number of spurious interrupts to exceed > the 100000 limit and display the warning above. Also note that by adding the > 3 second delay, NVIDIA devices with device ID 0x0FF* hit this problem 100% of > the time. > > darcari noticed that removing the pci_intx_for_msi() call resulted in a > stable system. After further discussions with Myron and Alex, Alex came up > idea of keeping the intx disabled during shutdown implemented below. > > ----8<---- > > The following unhandled IRQ warning is seen during shutdown: > > irq 16: nobody cared (try booting with the "irqpoll" option) > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.2-1.el7_UNSUPPORTED.x86_64 #1 > Hardware name: Hewlett-Packard HP Z820 Workstation/158B, BIOS J63 v03.90 06/01/2016 > 0000000000000000 ffff88041f803e70 ffffffff81333bd5 ffff88041cb78200 > ffff88041cb7829c ffff88041f803e98 ffffffff810d9465 ffff88041cb78200 > 0000000000000000 0000000000000028 ffff88041f803ed0 ffffffff810d97bf > Call Trace: > <IRQ> [<ffffffff81333bd5>] dump_stack+0x63/0x8e > [<ffffffff810d9465>] __report_bad_irq+0x35/0xd0 > [<ffffffff810d97bf>] note_interrupt+0x20f/0x260 > [<ffffffff810d6b35>] handle_irq_event_percpu+0x45/0x60 > [<ffffffff810d6b7c>] handle_irq_event+0x2c/0x50 > [<ffffffff810da31a>] handle_fasteoi_irq+0x8a/0x150 > [<ffffffff8102edfb>] handle_irq+0xab/0x130 > [<ffffffff81082391>] ? _local_bh_enable+0x21/0x50 > [<ffffffff817064ad>] do_IRQ+0x4d/0xd0 > [<ffffffff81704502>] common_interrupt+0x82/0x82 > <EOI> [<ffffffff815d0181>] ? cpuidle_enter_state+0xc1/0x280 > [<ffffffff815d0174>] ? cpuidle_enter_state+0xb4/0x280 > [<ffffffff815d0377>] cpuidle_enter+0x17/0x20 > [<ffffffff810bf660>] cpu_startup_entry+0x220/0x3a0 > [<ffffffff816f6da7>] rest_init+0x77/0x80 > [<ffffffff81d8e147>] start_kernel+0x495/0x4a2 > [<ffffffff81d8daa0>] ? set_init_arg+0x55/0x55 > [<ffffffff81d8d120>] ? early_idt_handler_array+0x120/0x120 > [<ffffffff81d8d5d6>] x86_64_start_reservations+0x2a/0x2c > [<ffffffff81d8d715>] x86_64_start_kernel+0x13d/0x14c > > This occurs because the pci_msi_shutdown() and pci_msix_shutdown() functions > enable the legacy intx interrupt even though the device and driver were not > configured for legacy intx. > > This patch blocks the enabling of intx during system shutdown or reboot. > > Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx> > Cc: David Arcari <darcari@xxxxxxxxxx> > Cc: Myron Stowe <mstowe@xxxxxxxxxx> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > --- > drivers/pci/msi.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > index bfdd0744b686..915cc29797f9 100644 > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -910,7 +910,8 @@ void pci_msi_shutdown(struct pci_dev *dev) > desc = first_pci_msi_entry(dev); > > pci_msi_set_enable(dev, 0); > - pci_intx_for_msi(dev, 1); > + if (system_state == SYSTEM_RUNNING || system_state == SYSTEM_BOOTING) > + pci_intx_for_msi(dev, 1); > dev->msi_enabled = 0; > > /* Return the device with MSI unmasked as initial states */ > @@ -1024,7 +1025,8 @@ void pci_msix_shutdown(struct pci_dev *dev) > } > > pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0); > - pci_intx_for_msi(dev, 1); > + if (system_state == SYSTEM_RUNNING || system_state == SYSTEM_BOOTING) > + pci_intx_for_msi(dev, 1); > dev->msix_enabled = 0; > pcibios_alloc_irq(dev); > } > -- > 1.7.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
