CVE-2024-50094

In the Linux kernel, the following vulnerability has been resolved:

sfc: Don't invoke xdp_do_flush() from netpoll.

Yury reported a crash in the sfc driver originated from netpoll_send_udp(). 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 xdp_do_flush() unconditionally, leading to crash because bpf_net_context was never assigned.

Invoke xdp_do_flush() only if budget is not zero.

This vulnerability is rated as Moderate severity because exploitation leads to a system crash (denial of service) but requires specialized Solarflare hardware and an active netpoll or netconsole configuration. Supported Red Hat Enterprise Linux releases are not affected because the upstream regression was introduced in newer kernel versions than those maintained in enterprise distributions. Exposure is limited to environments running affected upstream or community kernels equipped with Solarflare network adapters handling netconsole traffic.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.