[PATCH net-next v2 0/6] selftests: net: page_poll allocation error injection

[PATCH net-next v2 0/6] selftests: net: page_poll allocation error injection

[Jakub Kicinski]

Add a test for exercising driver memory allocation failure paths.
page pool is a bit tricky to inject errors into at the page allocator
level because of the bulk alloc and recycling, so add explicit error
injection support "in front" of the caches.

Add a test to exercise that using only the standard APIs.
This is the first useful test for the new tests with an endpoint.
There's no point testing netdevsim here, so this is also the first
HW-only test in Python.

I'm not super happy with the traffic generation using iperf3,
my initial approach was to use mausezahn. But it turned out to be
5x slower in terms of PPS. Hopefully this is good enough for now.

v2:
 - fix the string formatting for tool wrapper change (patch 3)
 - fix import order for load.py
v1: https://lore.kernel.org/all/20240426232400.624864-1-kuba@kernel.org/

Jakub Kicinski (6):
  net: page_pool: support error injection
  selftests: drv-net-hw: support using Python from net hw tests
  selftests: net: py: extract tool logic
  selftests: net: py: avoid all ports < 10k
  selftests: drv-net: support generating iperf3 load
  selftests: drv-net-hw: add test for memory allocation failures with
    page pool

 net/core/page_pool.c                          |   2 +
 tools/testing/selftests/Makefile              |   2 +-
 .../testing/selftests/drivers/net/hw/Makefile |   2 +
 .../drivers/net/hw/lib/py/__init__.py         |  16 +++
 .../selftests/drivers/net/hw/pp_alloc_fail.py | 129 ++++++++++++++++++
 .../selftests/drivers/net/lib/py/__init__.py  |   1 +
 .../selftests/drivers/net/lib/py/env.py       |  10 +-
 .../selftests/drivers/net/lib/py/load.py      |  41 ++++++
 tools/testing/selftests/net/lib/py/ksft.py    |   4 +
 tools/testing/selftests/net/lib/py/utils.py   |  14 +-
 10 files changed, 214 insertions(+), 7 deletions(-)
 create mode 100644 tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
 create mode 100755 tools/testing/selftests/drivers/net/hw/pp_alloc_fail.py
 create mode 100644 tools/testing/selftests/drivers/net/lib/py/load.py

-- 
2.44.0

[PATCH net-next v2 1/6] net: page_pool: support error injection

[Jakub Kicinski]

Because of caching / recycling using the general page allocation
failures to induce errors in page pool allocation is very hard.
Add direct error injection support to page_pool_alloc_pages().

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: hawk@kernel.org
CC: ilias.apalodimas@linaro.org
---
 net/core/page_pool.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 273c24429bce..8bcc7014a61a 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -5,6 +5,7 @@
  *	Copyright (C) 2016 Red Hat, Inc.
  */
 
+#include <linux/error-injection.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
@@ -550,6 +551,7 @@ struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp)
 	return page;
 }
 EXPORT_SYMBOL(page_pool_alloc_pages);
+ALLOW_ERROR_INJECTION(page_pool_alloc_pages, NULL);
 
 /* Calculate distance between two u32 values, valid if distance is below 2^(31)
  *  https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution
-- 
2.44.0

[PATCH net-next v2 2/6] selftests: drv-net-hw: support using Python from net hw tests

[Jakub Kicinski]

We created a separate directory for HW-only tests, recently.
Glue in the Python test library there, Python is a bit annoying
when it comes to using library code located "lower"
in the directory structure.

Reuse the Env class, but let tests require non-nsim setup.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 tools/testing/selftests/Makefile                 |  2 +-
 tools/testing/selftests/drivers/net/hw/Makefile  |  1 +
 .../selftests/drivers/net/hw/lib/py/__init__.py  | 16 ++++++++++++++++
 .../testing/selftests/drivers/net/lib/py/env.py  | 10 ++++++++--
 4 files changed, 26 insertions(+), 3 deletions(-)
 create mode 100644 tools/testing/selftests/drivers/net/hw/lib/py/__init__.py

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 2c940e9c4ced..9039f3709aff 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -119,7 +119,7 @@ TARGETS_HOTPLUG = cpu-hotplug
 TARGETS_HOTPLUG += memory-hotplug
 
 # Networking tests want the net/lib target, include it automatically
-ifneq ($(filter net drivers/net,$(TARGETS)),)
+ifneq ($(filter net drivers/net drivers/net/hw,$(TARGETS)),)
 ifeq ($(filter net/lib,$(TARGETS)),)
 	INSTALL_DEP_TARGETS := net/lib
 endif
diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index 2259a39a70ed..95f32158b095 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -16,6 +16,7 @@ TEST_FILES := \
 	#
 
 TEST_INCLUDES := \
+	$(wildcard lib/py/*.py ../lib/py/*.py) \
 	../../../net/lib.sh \
 	../../../net/forwarding/lib.sh \
 	../../../net/forwarding/ipip_lib.sh \
diff --git a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
new file mode 100644
index 000000000000..b582885786f5
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import sys
+from pathlib import Path
+
+KSFT_DIR = (Path(__file__).parent / "../../../../..").resolve()
+
+try:
+    sys.path.append(KSFT_DIR.as_posix())
+    from net.lib.py import *
+    from drivers.net.lib.py import *
+except ModuleNotFoundError as e:
+    ksft_pr("Failed importing `net` library from kernel sources")
+    ksft_pr(str(e))
+    ktap_result(True, comment="SKIP")
+    sys.exit(4)
diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index e2ab637e56dc..5c8f695b2536 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -2,7 +2,7 @@
 
 import os
 from pathlib import Path
-from lib.py import KsftSkipEx
+from lib.py import KsftSkipEx, KsftXfailEx
 from lib.py import cmd, ip
 from lib.py import NetNS, NetdevSimDev
 from .remote import Remote
@@ -76,7 +76,7 @@ from .remote import Remote
     nsim_v4_pfx = "192.0.2."
     nsim_v6_pfx = "2001:db8::"
 
-    def __init__(self, src_path):
+    def __init__(self, src_path, nsim_test=None):
 
         self.env = _load_env_file(src_path)
 
@@ -88,7 +88,10 @@ from .remote import Remote
         self._ns_peer = None
 
         if "NETIF" in self.env:
+            if nsim_test is True:
+                raise KsftXfailEx("Test only works on netdevsim")
             self._check_env()
+
             self.dev = ip("link show dev " + self.env['NETIF'], json=True)[0]
 
             self.v4 = self.env.get("LOCAL_V4")
@@ -98,6 +101,9 @@ from .remote import Remote
             kind = self.env["REMOTE_TYPE"]
             args = self.env["REMOTE_ARGS"]
         else:
+            if nsim_test is False:
+                raise KsftXfailEx("Test does not work on netdevsim")
+
             self.create_local()
 
             self.dev = self._ns.nsims[0].dev
-- 
2.44.0

[PATCH net-next v2 3/6] selftests: net: py: extract tool logic

[Jakub Kicinski]

The main use of the ip() wrapper over cmd() is that it can parse JSON.
cmd("ip -j link show") will return stdout as a string, and test has
to call json.loads(). With ip("link show", json=True) the return value
will be already parsed.

More tools (ethtool, bpftool etc.) support the --json switch.
To avoid having to wrap all of them individually create a tool()
helper.

Switch from -j to --json (for ethtool).
While at it consume the netns attribute at the ip() level.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
v2:
 - use consistent quote type
 - use format string to force string conversion of NetNS class
---
 tools/testing/selftests/net/lib/py/utils.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/lib/py/utils.py b/tools/testing/selftests/net/lib/py/utils.py
index d3715e6c21f2..4930a90a64ea 100644
--- a/tools/testing/selftests/net/lib/py/utils.py
+++ b/tools/testing/selftests/net/lib/py/utils.py
@@ -56,10 +56,10 @@ import time
         return self.process(terminate=self.terminate)
 
 
-def ip(args, json=None, ns=None, host=None):
-    cmd_str = "ip "
+def tool(name, args, json=None, ns=None, host=None):
+    cmd_str = name + ' '
     if json:
-        cmd_str += '-j '
+        cmd_str += '--json '
     cmd_str += args
     cmd_obj = cmd(cmd_str, ns=ns, host=host)
     if json:
@@ -67,6 +67,12 @@ import time
     return cmd_obj
 
 
+def ip(args, json=None, ns=None, host=None):
+    if ns:
+        args = f'-netns {ns} ' + args
+    return tool('ip', args, json=json, host=host)
+
+
 def rand_port():
     """
     Get unprivileged port, for now just random, one day we may decide to check if used.
-- 
2.44.0

[PATCH net-next v2 4/6] selftests: net: py: avoid all ports < 10k

[Jakub Kicinski]

When picking TCP ports to use, avoid all below 10k.
This should lower the chance of collision or running
afoul whatever random policies may be on the host.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 tools/testing/selftests/net/lib/py/utils.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/lib/py/utils.py b/tools/testing/selftests/net/lib/py/utils.py
index 4930a90a64ea..b57d467afd0f 100644
--- a/tools/testing/selftests/net/lib/py/utils.py
+++ b/tools/testing/selftests/net/lib/py/utils.py
@@ -77,7 +77,7 @@ import time
     """
     Get unprivileged port, for now just random, one day we may decide to check if used.
     """
-    return random.randint(1024, 65535)
+    return random.randint(10000, 65535)
 
 
 def wait_port_listen(port, proto="tcp", ns=None, host=None, sleep=0.005, deadline=5):
-- 
2.44.0

[PATCH net-next v2 5/6] selftests: drv-net: support generating iperf3 load

[Jakub Kicinski]

While we are not very interested in testing performance
it's useful to be able to generate a lot of traffic.
iperf is the simplest way of getting relatively high PPS.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
v2:
 - fix import order in __init__.py
---
 .../selftests/drivers/net/lib/py/__init__.py  |  1 +
 .../selftests/drivers/net/lib/py/load.py      | 41 +++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/net/lib/py/load.py

diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py
index 4789c1a4282d..401e70f7f136 100644
--- a/tools/testing/selftests/drivers/net/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py
@@ -15,4 +15,5 @@ KSFT_DIR = (Path(__file__).parent / "../../../..").resolve()
     sys.exit(4)
 
 from .env import *
+from .load import *
 from .remote import Remote
diff --git a/tools/testing/selftests/drivers/net/lib/py/load.py b/tools/testing/selftests/drivers/net/lib/py/load.py
new file mode 100644
index 000000000000..abdb677bdb1c
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/lib/py/load.py
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0
+
+import time
+
+from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen
+
+class GenerateTraffic:
+    def __init__(self, env):
+        env.require_cmd("iperf3", remote=True)
+
+        self.env = env
+
+        port = rand_port()
+        self._iperf_server = cmd(f"iperf3 -s -p {port}", background=True)
+        wait_port_listen(port)
+        time.sleep(0.1)
+        self._iperf_client = cmd(f"iperf3 -c {env.addr} -P 16 -p {port} -t 86400",
+                                 background=True, host=env.remote)
+
+        # Wait for traffic to ramp up
+        pkt = ip("-s link show dev " + env.ifname, json=True)[0]["stats64"]["rx"]["packets"]
+        for _ in range(50):
+            time.sleep(0.1)
+            now = ip("-s link show dev " + env.ifname, json=True)[0]["stats64"]["rx"]["packets"]
+            if now - pkt > 1000:
+                return
+            pkt = now
+        self.stop(verbose=True)
+        raise Exception("iperf3 traffic did not ramp up")
+
+    def stop(self, verbose=None):
+        self._iperf_client.process(terminate=True)
+        if verbose:
+            ksft_pr(">> Client:")
+            ksft_pr(self._iperf_client.stdout)
+            ksft_pr(self._iperf_client.stderr)
+        self._iperf_server.process(terminate=True)
+        if verbose:
+            ksft_pr(">> Server:")
+            ksft_pr(self._iperf_server.stdout)
+            ksft_pr(self._iperf_server.stderr)
-- 
2.44.0

[PATCH net-next v2 6/6] selftests: drv-net-hw: add test for memory allocation failures with page pool

[Jakub Kicinski]

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
 
-- 
2.44.0

Re: [PATCH net-next v2 0/6] selftests: net: page_poll allocation error injection

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 29 Apr 2024 07:44:20 -0700 you wrote:
> Add a test for exercising driver memory allocation failure paths.
> page pool is a bit tricky to inject errors into at the page allocator
> level because of the bulk alloc and recycling, so add explicit error
> injection support "in front" of the caches.
> 
> Add a test to exercise that using only the standard APIs.
> This is the first useful test for the new tests with an endpoint.
> There's no point testing netdevsim here, so this is also the first
> HW-only test in Python.
> 
> [...]

Here is the summary with links:
  - [net-next,v2,1/6] net: page_pool: support error injection
    https://git.kernel.org/netdev/net-next/c/12b6c3a0380a
  - [net-next,v2,2/6] selftests: drv-net-hw: support using Python from net hw tests
    https://git.kernel.org/netdev/net-next/c/ff4b2bfa63bd
  - [net-next,v2,3/6] selftests: net: py: extract tool logic
    https://git.kernel.org/netdev/net-next/c/32a4ca1361d7
  - [net-next,v2,4/6] selftests: net: py: avoid all ports < 10k
    https://git.kernel.org/netdev/net-next/c/ee2512d6bf41
  - [net-next,v2,5/6] selftests: drv-net: support generating iperf3 load
    https://git.kernel.org/netdev/net-next/c/0f0cdf312ecc
  - [net-next,v2,6/6] selftests: drv-net-hw: add test for memory allocation failures with page pool
    https://git.kernel.org/netdev/net-next/c/9da271f825e4

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html