x86: Fix 32-bit x86 MSI-X allocation leakage

commit 9d9ad4b51d2b29b5bbeb4011f5e76f7538119cf9 upstream

This bug was introduced in the 2.6.24 lguest tree merge, where
MSI-X vector allocation will eventually fail.  The cause is the new
bit array tracking used vectors is not getting cleared properly on
IRQ destruction on the 32-bit APIC code.

This can be seen easily using the ixgbe 10 GbE driver on multi-core
systems by simply loading and unloading the driver a few times.
Depending on the number of available vectors on the host system, the
MSI-X allocation will eventually fail, and the driver will only be
able to use legacy interrupts.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 232fdebdccaa63f642bfeb68d93127481e3a85e3..9994c52ce8f439cff64b9d0f712a17e428b83c4b 100644 (file)
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2478,6 +2478,7 @@ void destroy_irq(unsigned int irq)
        dynamic_irq_cleanup(irq);
 
        spin_lock_irqsave(&vector_lock, flags);
+       clear_bit(irq_vector[irq], used_vectors);
        irq_vector[irq] = 0;
        spin_unlock_irqrestore(&vector_lock, flags);
 }