Commit d1f3dbad authored by Mohsin Bashir's avatar Mohsin Bashir Committed by Jakub Kicinski
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selftests: drv-net: Wait for bkg socat to start 



Currently, UDP exchange is prone to failure when cmd attempt to send data
while socat in bkg is not ready. Since, the behavior is probabilistic, this
can result in flakiness for XDP tests. While testing
test_xdp_native_tx_mb() on netdevsim, a failure rate of around 1% in 500
500 iterations was observed.

Use wait_port_listen() to ensure that the bkg socat is started and ready to
receive before cmd start sending. With proposed changes, a re-run of the
same test passed 100% of time.

Signed-off-by: default avatarMohsin Bashir <mohsin.bashr@gmail.com>
Link: https://patch.msgid.link/20250724235140.2645885-1-mohsin.bashr@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8020ca54

tools/testing/selftests/drivers/net/xdp.py

+3 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ from enum import Enum 


from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_ne, ksft_pr

from lib.py import KsftFailEx, NetDrvEpEnv, EthtoolFamily, NlError

from lib.py import bkg, cmd, rand_port

from lib.py import bkg, cmd, rand_port, wait_port_listen

from lib.py import ip, bpftool, defer
@@ -70,6 +70,7 @@ def _exchg_udp(cfg, port, test_string): 
    tx_udp_cmd = f"echo -n {test_string} | socat -t 2 -u STDIN UDP:{cfg.baddr}:{port}"



    with bkg(rx_udp_cmd, exit_wait=True) as nc:

        wait_port_listen(port, proto="udp")

        cmd(tx_udp_cmd, host=cfg.remote, shell=True)



    return nc.stdout.strip()
@@ -310,6 +311,7 @@ def test_xdp_native_tx_mb(cfg): 
    tx_udp = f"echo {test_string} | socat -t 2 -u STDIN UDP:{cfg.baddr}:{port}"



    with bkg(rx_udp, host=cfg.remote, exit_wait=True) as rnc:

        wait_port_listen(port, proto="udp", host=cfg.remote)

        cmd(tx_udp, host=cfg.remote, shell=True)



    stats = _get_stats(prog_info['maps']['map_xdp_stats'])