[patch 02/14] x86/irq: Validate that irq descriptor is still active

From: Thomas Gleixner
Date: Thu Dec 31 2015 - 11:31:57 EST


In fixup_irqs() we unconditionally dereference the irq chip of an irq
descriptor. The descriptor might still be valid, but already cleaned up,
i.e. the chip removed. Add a check for this condition.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/irq.c | 9 +++++++++
1 file changed, 9 insertions(+)

--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -470,6 +470,15 @@ void fixup_irqs(void)
}

chip = irq_data_get_irq_chip(data);
+ /*
+ * The interrupt descriptor might have been cleaned up
+ * already, but it is not yet removed from the radix tree
+ */
+ if (!chip) {
+ raw_spin_unlock(&desc->lock);
+ continue;
+ }
+
if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
chip->irq_mask(data);



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