tree e758a1cbc47dcaff5e9c13ee2b336dd48994c881
parent bf9bae0ea6ec7013ef37b19fbbf29b62a35474fb
parent 1bf9116d0866a649104a5dfa008c302ad54d1e02
author Daniel Borkmann <daniel@iogearbox.net> 1533844245 +0200
committer Daniel Borkmann <daniel@iogearbox.net> 1533844245 +0200

Merge branch 'bpf-fix-cpu-and-devmap-teardown'

Jesper Dangaard Brouer says:

====================
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).
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>