Describe CVE-2021-47164.
What is CVE-2021-47164?
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: Fix null deref accessing lag dev

It could be the lag dev is null so stop processing the event.
In bond_enslave() the active/backup slave being set before setting the
upper dev so first event is without an upper dev.
After setting the upper dev with bond_master_upper_dev_link() there is
a second event and in that event we have an upper dev..