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

Vulnerability 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.

References

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