local_irq_restore -> raw_local_irq_restore -> irq_restore_epilog ->
smtc_ipi_replay -> smtc_ipi_dq -> spin_unlock_irqrestore ->
_spin_unlock_irqrestore -> local_irq_restore
The recursion does abort when there is no more IPI queued for a CPU, so
this isn't usually fatal which is why we got away with this for so long
until this was discovered by code inspection.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
