In the Linux kernel, the following vulnerability has been resolved: IB/ipoib: Fix mcast list locking Releasing the `priv->lock` while iterating the `priv->multicast_list` in `ipoib_mcast_join_task()` opens a window for `ipoib_mcast_dev_flush()` to remove the items while in the middle of iteration. If the mcast is removed while the lock was dropped, the for loop spins forever resulting in a hard lockup (as was reported on RHEL 4.18.0-372.75.1.el8_6 kernel): Task A (kworker/u72:2 below) | Task B (kworker/u72:0 below) -----------------------------------+----------------------------------- ipoib_mcast_join_task(work) | ipoib_ib_dev_flush_light(work) spin_lock_irq(&priv->lock) | __ipoib_ib_dev_flush(priv, ...) list_for_each_entry(mcast, | ipoib_mcast_dev_flush(dev = priv->dev) &priv->multicast_list, list) | ipoib_mcast_join(dev, mcast) | spin_unlock_irq(&priv->lock) | | …