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Commit 0ca4b6b0 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
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x86: Fix interrupt leak due to migration 



When we migrate an interrupt from one CPU to another, we set the
move_in_progress flag and clean up the vectors later once they're not
being used.  If you're unlucky and call destroy_irq() before the vectors
become un-used, the move_in_progress flag is never cleared, which causes
the interrupt to become unusable.

This was discovered by Jesse Brandeburg for whom it manifested as an
MSI-X device refusing to use MSI-X mode when the driver was unloaded
and reloaded repeatedly.

Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 23918b03

arch/x86/kernel/io_apic.c

+14 −0
Original line number Diff line number Diff line
@@ -1140,6 +1140,20 @@ static void __clear_irq_vector(int irq) 


	cfg->vector = 0;

	cpus_clear(cfg->domain);



	if (likely(!cfg->move_in_progress))

		return;

	cpus_and(mask, cfg->old_domain, cpu_online_map);

	for_each_cpu_mask_nr(cpu, mask) {

		for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;

								vector++) {

			if (per_cpu(vector_irq, cpu)[vector] != irq)

				continue;

			per_cpu(vector_irq, cpu)[vector] = -1;

			break;

		}

	}

	cfg->move_in_progress = 0;

}



void __setup_vector_irq(int cpu)