In the Linux kernel, the following vulnerability has been resolved:
ice: avoid bpf_prog refcount underflow
Ice driver has the routines for managing XDP resources that are shared
between ndo_bpf op and VSI rebuild flow. The latter takes place for
example when user changes queue count on an interface via ethtool's
set_channels().
There is an issue around the bpf_prog refcounting when VSI is being
rebuilt - since ice_prepare_xdp_rings() is called with vsi->xdp_prog as
an argument that is used later on by ice_vsi_assign_bpf_prog(), same
bpf_prog pointers are swapped with each other. Then it is also
interpreted as an 'old_prog' which in turn causes us to call
bpf_prog_put on it that will decrement its refcount.
Below splat can be interpreted in a way that due to zero refcount of a
bpf_prog it is wiped out from the system while kernel still tries to
refer to it:
