On 2018年02月22日 15:54, Sergei Shtylyov wrote:
On 2/22/2018 9:24 AM, Jason Wang wrote:
Commit 762c330d670e ("tuntap: add missing xdp flush") tries to fix the
devmap stall caused by missed xdp flush by counting the pending xdp
redirected packets and flush when it exceeds NAPI_POLL_WEIGHT or
MSG_MORE is clear. This may lead BUG() since xdp_do_flush() was
Lead to BUG().
called under process context with preemption enabled. Simply disable
preemption may silent the warning but be not enough since process may
move between different CPUS during a batch which cause xdp_do_flush()
misses some CPU where the process run previously. Consider the several
fallouts, that commit was reverted. To fix the issue correctly, we can
simply calling xdp_do_flush() immediately after xdp_do_redirect(),
a side effect is that this removes any possibility of batching which
could be addressed in the future.
Reported-by: Christoffer Dall <christoffer.d...@linaro.org>
Fixes: 762c330d670e ("tuntap: add missing xdp flush")
Signed-off-by: Jason Wang <jasow...@redhat.com>
My bad, let me post v3.