Commits
Christoffer Dall committed 2cccbb368a2
KVM: arm64: vgic-its: Plug race in vgic_put_irq
Right now the following sequence of events can happen:
1. Thread X calls vgic_put_irq
2. Thread Y calls vgic_add_lpi
3. Thread Y gets lpi_list_lock
4. Thread X drops the ref count to 0 and blocks on lpi_list_lock
5. Thread Y finds the irq via the lpi_list_lock, raises the ref
count to 1, and release the lpi_list_lock.
6. Thread X proceeds and frees the irq.
Avoid this by holding the spinlock around the kref_put.
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>