samples/bpf, xdpsock: Fix race when running for fix duration of time
[ Upstream commit 8fa42d78f6354bb96ad3a079dcbef528ca9fa9e0 ]
When running xdpsock for a fix duration of time before terminating
using --duration=<n>, there is a race condition that may cause xdpsock
to terminate immediately.
When running for a fixed duration of time the check to determine when to
terminate execution is in is_benchmark_done() and is being executed in
the context of the poller thread,
if (opt_duration > 0) {
unsigned long dt = (get_nsecs() - start_time);
if (dt >= opt_duration)
benchmark_done = true;
}
However start_time is only set after the poller thread have been
created. This leaves a small window when the poller thread is starting
and calls is_benchmark_done() for the first time that start_time is not
yet set. In that case start_time have its initial value of 0 and the
duration check fails as it do not correlate correctly for the
applications start time and immediately sets benchmark_done which in
turn terminates the xdpsock application.
Fix this by setting start_time before creating the poller thread.
Fixes: d3f11b018f6c ("samples/bpf: xdpsock: Add duration option to specify how long to run")
Signed-off-by: Niklas Söderlund <[email protected]>
Signed-off-by: Simon Horman <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
1 file changed
