On 08/08/2018 11:00 PM, Jesper Dangaard Brouer wrote: > Removing entries from cpumap and devmap, goes through a number of > syncronization steps to make sure no new xdp_frames can be enqueued. > But there is a small chance, that xdp_frames remains which have not > been flushed/processed yet. Flushing these during teardown, happens > from RCU context and not as usual under RX NAPI context. > > The optimization introduced in commt 389ab7f01af9 ("xdp: introduce > xdp_return_frame_rx_napi"), missed that the flush operation can also > be called from RCU context. Thus, we cannot always use the > xdp_return_frame_rx_napi call, which take advantage of the protection > provided by XDP RX running under NAPI protection. > > The samples/bpf xdp_redirect_cpu have a --stress-mode, that is > adjusted to easier reproduce (verified by Red Hat QA).
Applied to bpf, thanks Jesper!