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Commit df54c493 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/irq: Protect smp_cleanup_move 



smp_cleanup_move fiddles without protection in the interrupt
descriptors and the vector array. A concurrent irq setup/teardown or
affinity setting can pull the rug under that operation.

Add proper locking.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: http://lkml.kernel.org/r/20150802203609.222975294@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent ad3f8d5a

arch/x86/kernel/apic/vector.c

+14 −4
Original line number Diff line number Diff line
@@ -539,6 +539,9 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void) 


	entering_ack_irq();



	/* Prevent vectors vanishing under us */

	raw_spin_lock(&vector_lock);



	me = smp_processor_id();

	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {

		int irq;
@@ -546,6 +549,7 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void) 
		struct irq_desc *desc;

		struct apic_chip_data *data;



	retry:

		irq = __this_cpu_read(vector_irq[vector]);



		if (irq <= VECTOR_UNDEFINED)
@@ -555,12 +559,16 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void) 
		if (!desc)

			continue;



		if (!raw_spin_trylock(&desc->lock)) {

			raw_spin_unlock(&vector_lock);

			cpu_relax();

			raw_spin_lock(&vector_lock);

			goto retry;

		}



		data = apic_chip_data(&desc->irq_data);

		if (!data)

			continue;



		raw_spin_lock(&desc->lock);



			goto unlock;

		/*

		 * Check if the irq migration is in progress. If so, we

		 * haven't received the cleanup request yet for this irq.
@@ -589,6 +597,8 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void) 
		raw_spin_unlock(&desc->lock);

	}



	raw_spin_unlock(&vector_lock);



	exiting_irq();

}