CVE-2022-48985 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: mana: Fix race on per-CQ variable napi work_done

After calling napi_complete_done() the NAPIF_STATE_SCHED bit may be cleared and another CPU can start napi thread and access per-CQ variable cq->work_done. If the other thread (for example from busy_poll) sets it to a value >= budget this thread will continue to run when it should stop and cause memory corruption and panic.

To fix this issue save the per-CQ work_done variable in a local variable before napi_complete_done() so it won’t be corrupted by a possible concurrent thread after napi_complete_done().

Also add a flag bit to advertise to the NIC firmware: the NAPI work_done variable race is fixed so the driver is able to reliably support features like busy_poll.

Reference

https://git.kernel.org/stable/c/fe50a9bbeb1f042e756c5cfa7708112c944368de https://git.kernel.org/stable/c/6740d8572ccd1bca50d8a1ca2bedc333f50ed5f3 https://git.kernel.org/stable/c/18010ff776fa42340efc428b3ea6d19b3e7c7b21