3.19.8-ckt15 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------ From: Thomas Gleixner <[email protected]> commit e23b257c293ce4bcc8cabb2aa3097b6ed8a8261a upstream. setup_ioapic_dest() calls irqchip->irq_set_affinity() completely unprotected. That's wrong in several aspects: - it opens a race window where irq_set_affinity() can be interrupted and the irq chip left in unconsistent state. - it triggers a lockdep splat when we fix the vector race for 4.3+ because vector lock is taken with interrupts enabled. The proper calling convention is irq descriptor lock held and interrupts disabled. Reported-and-tested-by: Borislav Petkov <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Jiang Liu <[email protected]> Cc: Jeremiah Mahler <[email protected]> Cc: [email protected] Cc: Guenter Roeck <[email protected]> Cc: Joe Lawrence <[email protected]> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1601140919420.3575@nanos Signed-off-by: Thomas Gleixner <[email protected]> [ kamal: backport to 3.19-stable: context ] Signed-off-by: Kamal Mostafa <[email protected]> --- arch/x86/kernel/apic/io_apic.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 3f5f604..43a541e 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2665,6 +2665,7 @@ void __init setup_ioapic_dest(void) { int pin, ioapic, irq, irq_entry; const struct cpumask *mask; + struct irq_desc *desc; struct irq_data *idata; if (skip_ioapic_setup == 1) @@ -2679,7 +2680,9 @@ void __init setup_ioapic_dest(void) if (irq < 0 || !mp_init_irq_at_boot(ioapic, irq)) continue; - idata = irq_get_irq_data(irq); + desc = irq_to_desc(irq); + raw_spin_lock_irq(&desc->lock); + idata = irq_desc_get_irq_data(desc); /* * Honour affinities which have been set in early boot @@ -2690,6 +2693,7 @@ void __init setup_ioapic_dest(void) mask = apic->target_cpus(); x86_io_apic_ops.set_affinity(idata, mask, false); + raw_spin_unlock_irq(&desc->lock); } } -- 1.9.1
