Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 05/47] x86/irq: Call chip->irq_set_affinity in proper context | Date | Tue, 9 Feb 2016 14:44:19 -0800 |
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3.19.8-ckt15 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Thomas Gleixner <tglx@linutronix.de>
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 <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Jeremiah Mahler <jmmahler@gmail.com> Cc: andy.shevchenko@gmail.com Cc: Guenter Roeck <linux@roeck-us.net> Cc: Joe Lawrence <joe.lawrence@stratus.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1601140919420.3575@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ kamal: backport to 3.19-stable: context ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- 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
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