Bugs in memory allocation failure paths are quite common. Add a test exercising those paths based on qstat and page pool failure hook.
Running on bnxt:
# ./drivers/net/hw/pp_alloc_fail.py KTAP version 1 1..1 # ethtool -G change retval: success ok 1 pp_alloc_fail.test_pp_alloc # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
I initially wrote this test to validate commit be43b7489a3c ("net/mlx5e: RX, Fix page_pool allocation failure recovery for striding rq") but mlx5 still doesn't have qstat. So I run it on bnxt, and while bnxt survives I found the problem fixed in commit 730117730709 ("eth: bnxt: fix counting packets discarded due to OOM and netpoll").
Reviewed-by: Willem de Bruijn willemb@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org --- .../testing/selftests/drivers/net/hw/Makefile | 1 + .../selftests/drivers/net/hw/pp_alloc_fail.py | 129 ++++++++++++++++++ tools/testing/selftests/net/lib/py/ksft.py | 4 + 3 files changed, 134 insertions(+) create mode 100755 tools/testing/selftests/drivers/net/hw/pp_alloc_fail.py
diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile index 95f32158b095..1dd732855d76 100644 --- a/tools/testing/selftests/drivers/net/hw/Makefile +++ b/tools/testing/selftests/drivers/net/hw/Makefile @@ -9,6 +9,7 @@ TEST_PROGS = \ hw_stats_l3.sh \ hw_stats_l3_gre.sh \ loopback.sh \ + pp_alloc_fail.py \ #
TEST_FILES := \ diff --git a/tools/testing/selftests/drivers/net/hw/pp_alloc_fail.py b/tools/testing/selftests/drivers/net/hw/pp_alloc_fail.py new file mode 100755 index 000000000000..026d98976c35 --- /dev/null +++ b/tools/testing/selftests/drivers/net/hw/pp_alloc_fail.py @@ -0,0 +1,129 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 + +import time +import os +from lib.py import ksft_run, ksft_exit, ksft_pr +from lib.py import KsftSkipEx, KsftFailEx +from lib.py import NetdevFamily, NlError +from lib.py import NetDrvEpEnv +from lib.py import cmd, tool, GenerateTraffic + + +def _write_fail_config(config): + for key, value in config.items(): + with open("/sys/kernel/debug/fail_function/" + key, "w") as fp: + fp.write(str(value) + "\n") + + +def _enable_pp_allocation_fail(): + if not os.path.exists("/sys/kernel/debug/fail_function"): + raise KsftSkipEx("Kernel built without function error injection (or DebugFS)") + + if not os.path.exists("/sys/kernel/debug/fail_function/page_pool_alloc_pages"): + with open("/sys/kernel/debug/fail_function/inject", "w") as fp: + fp.write("page_pool_alloc_pages\n") + + _write_fail_config({ + "verbose": 0, + "interval": 511, + "probability": 100, + "times": -1, + }) + + +def _disable_pp_allocation_fail(): + if not os.path.exists("/sys/kernel/debug/fail_function"): + return + + if os.path.exists("/sys/kernel/debug/fail_function/page_pool_alloc_pages"): + with open("/sys/kernel/debug/fail_function/inject", "w") as fp: + fp.write("\n") + + _write_fail_config({ + "probability": 0, + "times": 0, + }) + + +def test_pp_alloc(cfg, netdevnl): + def get_stats(): + return netdevnl.qstats_get({"ifindex": cfg.ifindex}, dump=True)[0] + + def check_traffic_flowing(): + stat1 = get_stats() + time.sleep(1) + stat2 = get_stats() + if stat2['rx-packets'] - stat1['rx-packets'] < 15000: + raise KsftFailEx("Traffic seems low:", stat2['rx-packets'] - stat1['rx-packets']) + + + try: + stats = get_stats() + except NlError as e: + if e.nl_msg.error == -95: + stats = {} + else: + raise + if 'rx-alloc-fail' not in stats: + raise KsftSkipEx("Driver does not report 'rx-alloc-fail' via qstats") + + set_g = False + traffic = None + try: + traffic = GenerateTraffic(cfg) + + check_traffic_flowing() + + _enable_pp_allocation_fail() + + s1 = get_stats() + time.sleep(3) + s2 = get_stats() + + if s2['rx-alloc-fail'] - s1['rx-alloc-fail'] < 1: + raise KsftSkipEx("Allocation failures not increasing") + if s2['rx-alloc-fail'] - s1['rx-alloc-fail'] < 100: + raise KsftSkipEx("Allocation increasing too slowly", s2['rx-alloc-fail'] - s1['rx-alloc-fail'], + "packets:", s2['rx-packets'] - s1['rx-packets']) + + # Basic failures are fine, try to wobble some settings to catch extra failures + check_traffic_flowing() + g = tool("ethtool", "-g " + cfg.ifname, json=True)[0] + if 'rx' in g and g["rx"] * 2 <= g["rx-max"]: + new_g = g['rx'] * 2 + elif 'rx' in g: + new_g = g['rx'] // 2 + else: + new_g = None + + if new_g: + set_g = cmd(f"ethtool -G {cfg.ifname} rx {new_g}", fail=False).ret == 0 + if set_g: + ksft_pr("ethtool -G change retval: success") + else: + ksft_pr("ethtool -G change retval: did not succeed", new_g) + else: + ksft_pr("ethtool -G change retval: did not try") + + time.sleep(0.1) + check_traffic_flowing() + finally: + _disable_pp_allocation_fail() + if traffic: + traffic.stop() + time.sleep(0.1) + if set_g: + cmd(f"ethtool -G {cfg.ifname} rx {g['rx']}") + + +def main() -> None: + netdevnl = NetdevFamily() + with NetDrvEpEnv(__file__, nsim_test=False) as cfg: + + ksft_run([test_pp_alloc], args=(cfg, netdevnl, )) + ksft_exit() + + +if __name__ == "__main__": + main() diff --git a/tools/testing/selftests/net/lib/py/ksft.py b/tools/testing/selftests/net/lib/py/ksft.py index f84e9fdd0032..4769b4eb1ea1 100644 --- a/tools/testing/selftests/net/lib/py/ksft.py +++ b/tools/testing/selftests/net/lib/py/ksft.py @@ -11,6 +11,10 @@ KSFT_RESULT = None KSFT_RESULT_ALL = True
+class KsftFailEx(Exception): + pass + + class KsftSkipEx(Exception): pass