In the Linux kernel, the following vulnerability has been resolved:
sfc: Don't invoke xdpdoflush() from netpoll.
Yury reported a crash in the sfc driver originated from netpollsendudp(). The netconsole sends a message and then netpoll invokes the driver's NAPI function with a budget of zero. It is dedicated to allow driver to free TX resources, that it may have used while sending the packet.
In the netpoll case the driver invokes xdpdoflush() unconditionally, leading to crash because bpfnetcontext was never assigned.
Invoke xdpdoflush() only if budget is not zero.