virtio_ccw_int_handler() takes vcdev->irq_lock around its
vring_interrupt() calls only when VIRTIO_HARDEN_NOTIFICATION is enabled.
The virtio shutdown path calls synchronize_cbs() even when notification
hardening is disabled. virtio_reset_device() now does so after the
transport reset too.
For classic interrupts, synchronize_cbs() takes vcdev->irq_lock for
writing, but the interrupt handler does not take the matching read
lock in that configuration. synchronize_cbs() can return while a
callback is still running.
Take the read lock unconditionally so the write side can synchronize
with the callbacks.
Fixes: 8bd2fa086a04 ("virtio: break and reset virtio devices on
device_shutdown()")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <[email protected]>
---
drivers/s390/virtio/virtio_ccw.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index b90299205698..552d77998012 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -1204,13 +1204,11 @@ static void virtio_ccw_int_handler(struct ccw_device
*cdev,
vcdev->err = -EIO;
}
virtio_ccw_check_activity(vcdev, activity);
-#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
/*
* Paired with virtio_ccw_synchronize_cbs() and interrupts are
* disabled here.
*/
read_lock(&vcdev->irq_lock);
-#endif
for_each_set_bit(i, indicators(vcdev),
sizeof(*indicators(vcdev)) * BITS_PER_BYTE) {
/* The bit clear must happen before the vring kick. */
@@ -1219,9 +1217,7 @@ static void virtio_ccw_int_handler(struct ccw_device
*cdev,
vq = virtio_ccw_vq_by_ind(vcdev, i);
vring_interrupt(0, vq);
}
-#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
read_unlock(&vcdev->irq_lock);
-#endif
if (test_bit(0, indicators2(vcdev))) {
virtio_config_changed(&vcdev->vdev);
clear_bit(0, indicators2(vcdev));
--
2.39.5 (Apple Git-154)
