Merge branch 'bpf-fix-cpu-and-devmap-teardown'
Jesper Dangaard Brouer says:
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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).
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Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
