After working on the backport to Vivid, I'm not sure if the patch(Commit c0ff971) requested in this bug is applicable to Vivid and Trusty.
Commit c0ff971 disables interrupts when re-routing legacy IRQs. However, the functions affected by commit c0ff971 were not added until v4.2-rc1 by commit: '49c7e60 x86/irq: Implement callbacks to enable hierarchical irqdomains on IOAPICs' Heirarchical irqdomains were not added until v4.2-rc1 as well, by commit: 'b5dc8e6 x86/irq: Use hierarchical irqdomain to manage CPU interrupt vectors' The reproducer listed in the description cannot be attempted since mp_setup_entry() and mp_register_handler() dont exist in the 3.19 or 3.13 kernels since they were added in 4.2-rc1 by commit 49c7e60. Is there a way to confirm and test that commit c0ff971 is needed in Vivid and Trusty? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1508593 Title: [Hyper-V] x86/ioapic: Disable interrupts when re-routing legacy IRQs Status in linux package in Ubuntu: In Progress Status in linux source package in Trusty: In Progress Status in linux source package in Vivid: In Progress Status in linux source package in Wily: Fix Committed Bug description: A sporadic hang with consequent crash is observed when booting Hyper-V Gen1 guests... Sauce request for upstream submission: https://lkml.org/lkml/2015/10/15/673 From Vitaly Kuznetsov <> Subject [PATCH] x86/ioapic: Disable interrupts when re-routing legacy IRQs Date Thu, 15 Oct 2015 19:42:23 +0200 A sporadic hang with consequent crash is observed when booting Hyper-V Gen1 guests: Call Trace: <IRQ> [<ffffffff810ab68d>] ? trace_hardirqs_off+0xd/0x10 [<ffffffff8107b616>] queue_work_on+0x46/0x90 [<ffffffff81365696>] ? add_interrupt_randomness+0x176/0x1d0 ... <EOI> [<ffffffff81471ddb>] ? _raw_spin_unlock_irqrestore+0x3b/0x60 [<ffffffff810c295e>] __irq_put_desc_unlock+0x1e/0x40 [<ffffffff810c5c35>] irq_modify_status+0xb5/0xd0 [<ffffffff8104adbb>] mp_register_handler+0x4b/0x70 [<ffffffff8104c55a>] mp_irqdomain_alloc+0x1ea/0x2a0 [<ffffffff810c7f10>] irq_domain_alloc_irqs_recursive+0x40/0xa0 [<ffffffff810c860c>] __irq_domain_alloc_irqs+0x13c/0x2b0 [<ffffffff8104b070>] alloc_isa_irq_from_domain.isra.1+0xc0/0xe0 [<ffffffff8104bfa5>] mp_map_pin_to_irq+0x165/0x2d0 [<ffffffff8104c157>] pin_2_irq+0x47/0x80 [<ffffffff81744253>] setup_IO_APIC+0xfe/0x802 ... [<ffffffff814631c0>] ? rest_init+0x140/0x140 The issue is easily reproducible with a simple instrumentation: if mdelay(10) is put between mp_setup_entry() and mp_register_handler() calls in mp_irqdomain_alloc() Hyper-V guest always fails to boot when re-routing IRQ0. The issue seems to be caused by the fact that we don't disable interrupts while doing IOPIC programming for legacy IRQs and IRQ0 actually happens. Decorate manipulations with legacy IRQs with local_irq_save()/ local_irq_restore(). Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ingo Molnar <mi...@redhat.com> Cc: "H. Peter Anvin" <h...@zytor.com> Cc: Jiang Liu <jiang....@linux.intel.com> Cc: Yinghai Lu <ying...@kernel.org> Cc: K. Y. Srinivasan <k...@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> --- It may make sense to have interrupts disabled for non-legacy IRQs as well but I'm unaware of any bugs with them at this moment. --- arch/x86/kernel/apic/io_apic.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 5c60bb1..9aac777 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2907,6 +2907,7 @@ int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq, struct irq_data *irq_data; struct mp_chip_data *data; struct irq_alloc_info *info = arg; + unsigned long flags = 0; if (!info || nr_irqs > 1) return -EINVAL; @@ -2939,11 +2940,16 @@ int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq, cfg = irqd_cfg(irq_data); add_pin_to_irq_node(data, ioapic_alloc_attr_node(info), ioapic, pin); + + if (virq < nr_legacy_irqs()) + local_irq_save(flags); if (info->ioapic_entry) mp_setup_entry(cfg, data, info->ioapic_entry); mp_register_handler(virq, data->trigger); - if (virq < nr_legacy_irqs()) + if (virq < nr_legacy_irqs()) { legacy_pic->mask(virq); + local_irq_restore(flags); + } apic_printk(APIC_VERBOSE, KERN_DEBUG "IOAPIC[%d]: Set routing entry (%d-%d -> 0x%x -> IRQ %d Mode:%i Active:%i Dest:%d)\n", -- 2.4.3 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1508593/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
