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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: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox 2008-11-20 14:09:33 -07:00 committed by Linus Torvalds
parent 23918b0306
commit 0ca4b6b001
1 changed files with 14 additions and 0 deletions
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14
arch/x86/kernel/io_apic.c
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@ -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)