Re: [PATCH v2] blackhole_dev: convert self-test to KUnit

On Sat, Feb 8, 2025 at 2:26 PM Tamir Duberstein tamird@gmail.com wrote:

Convert this very simple smoke test to a KUnit test.

Add a missing `htons` call that was spotted[0] by kernel test robot lkp@intel.com after initial conversion to KUnit.

Link: https://lore.kernel.org/oe-kbuild-all/202502090223.qCYMBjWT-lkp@intel.com/ [0] Signed-off-by: Tamir Duberstein tamird@gmail.com

---

I tested this using:

$ tools/testing/kunit/kunit.py run --arch arm64 --make_options LLVM=1 --kconfig_add CONFIG_NET=y blackholedev

Changes in v2:

• Add missing `htons` call. (kernel test robot lkp@intel.com)
• Link to v1: https://lore.kernel.org/r/20250207-blackholedev-kunit-convert-v1-1-8ef0dc1ff...

---

lib/Kconfig.debug | 20 ++++----- lib/Makefile | 2 +- ...{test_blackhole_dev.c => blackhole_dev_kunit.c} | 47 ++++++++-------------- tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/test_blackhole_dev.sh | 11 ----- 5 files changed, 29 insertions(+), 53 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 1af972a92d06..238321830993 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2557,15 +2557,6 @@ config TEST_BPF

      If unsure, say N.

-config TEST_BLACKHOLE_DEV

•   tristate "Test blackhole netdev functionality"
  

•   depends on m && NET
  

•   help
  

•     This builds the "test_blackhole_dev" module that validates the
  

•     data path through this blackhole netdev.
  

•     If unsure, say N.
  

config FIND_BIT_BENCHMARK tristate "Test find_bit functions" help @@ -2888,6 +2879,17 @@ config USERCOPY_KUNIT_TEST on the copy_to/from_user infrastructure, making sure basic user/kernel boundary testing is working.

+config BLACKHOLE_DEV_KUNIT_TEST

•   tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
  

•   depends on NET
  

•   depends on KUNIT
  

•   default KUNIT_ALL_TESTS
  

•   help
  

•     This builds the "blackhole_dev_kunit" module that validates the
  

•     data path through this blackhole netdev.
  

•     If unsure, say N.
  

config TEST_UDELAY tristate "udelay test driver" help diff --git a/lib/Makefile b/lib/Makefile index d5cfc7afbbb8..19ff6993c2bc 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -102,7 +102,6 @@ obj-$(CONFIG_TEST_RUNTIME) += tests/ obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o -obj-$(CONFIG_TEST_BLACKHOLE_DEV) += test_blackhole_dev.o obj-$(CONFIG_TEST_MEMINIT) += test_meminit.o obj-$(CONFIG_TEST_LOCKUP) += test_lockup.o obj-$(CONFIG_TEST_HMM) += test_hmm.o @@ -393,6 +392,7 @@ obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o obj-$(CONFIG_CRC_KUNIT_TEST) += crc_kunit.o obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o +obj-$(CONFIG_BLACKHOLE_DEV_KUNIT_TEST) += blackhole_dev_kunit.o

obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o

diff --git a/lib/test_blackhole_dev.c b/lib/blackhole_dev_kunit.c similarity index 68% rename from lib/test_blackhole_dev.c rename to lib/blackhole_dev_kunit.c index ec290ac2a0d9..06834ab35f43 100644 --- a/lib/test_blackhole_dev.c +++ b/lib/blackhole_dev_kunit.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /*

• • This module tests the blackhole_dev that is created during the

• • This tests the blackhole_dev that is created during the
  • net subsystem initialization. The test this module performs is
  • by injecting an skb into the stack with skb->dev as the
  • blackhole_dev and expects kernel to behave in a sane manner

@@ -9,9 +9,8 @@

• Copyright (c) 2018, Mahesh Bandewar maheshb@google.com

*/

-#include <linux/init.h> +#include <kunit/test.h> #include <linux/module.h> -#include <linux/printk.h> #include <linux/skbuff.h> #include <linux/netdevice.h> #include <linux/udp.h> @@ -25,17 +24,15 @@

#define UDP_PORT 1234

-static int __init test_blackholedev_init(void) +static void test_blackholedev(struct kunit *test) { struct ipv6hdr *ip6h; struct sk_buff *skb; struct udphdr *uh; int data_len;

•   int ret;
  
    skb = alloc_skb(SKB_SIZE, GFP_KERNEL);
  

•   if (!skb)
  

•           return -ENOMEM;
  

•   KUNIT_ASSERT_NOT_NULL(test, skb);
  
    /* Reserve head-room for the headers */
    skb_reserve(skb, HEAD_SIZE);
  

@@ -55,7 +52,7 @@ static int __init test_blackholedev_init(void) ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr)); skb_set_network_header(skb, 0); ip6h->hop_limit = 32;

•   ip6h->payload_len = data_len + sizeof(struct udphdr);
  

•   ip6h->payload_len = htons(data_len + sizeof(struct udphdr));
    ip6h->nexthdr = IPPROTO_UDP;
    ip6h->saddr = in6addr_loopback;
    ip6h->daddr = in6addr_loopback;
  

@@ -68,32 +65,20 @@ static int __init test_blackholedev_init(void) skb->dev = blackhole_netdev;

    /* Now attempt to send the packet */

•   ret = dev_queue_xmit(skb);
  

•   switch (ret) {
  

•   case NET_XMIT_SUCCESS:
  

•           pr_warn("dev_queue_xmit() returned NET_XMIT_SUCCESS\n");
  

•           break;
  

•   case NET_XMIT_DROP:
  

•           pr_warn("dev_queue_xmit() returned NET_XMIT_DROP\n");
  

•           break;
  

•   case NET_XMIT_CN:
  

•           pr_warn("dev_queue_xmit() returned NET_XMIT_CN\n");
  

•           break;
  

•   default:
  

•           pr_err("dev_queue_xmit() returned UNKNOWN(%d)\n", ret);
  

•   }
  

•   return 0;
  

•   KUNIT_EXPECT_EQ(test, dev_queue_xmit(skb), NET_XMIT_SUCCESS);
  

}

-static void __exit test_blackholedev_exit(void) -{

•   pr_warn("test_blackholedev module terminating.\n");
  

-} +static struct kunit_case blackholedev_cases[] = {

•   KUNIT_CASE(test_blackholedev),
  

•   {},
  

+};

+static struct kunit_suite blackholedev_suite = {

•   .name = "blackholedev",
  

•   .test_cases = blackholedev_cases,
  

+};

-module_init(test_blackholedev_init); -module_exit(test_blackholedev_exit); +kunit_test_suite(blackholedev_suite);

MODULE_AUTHOR("Mahesh Bandewar maheshb@google.com"); MODULE_DESCRIPTION("module test of the blackhole_dev"); diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 73ee88d6b043..afa4bcdc5833 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -7,7 +7,7 @@ CFLAGS += -I../../../../usr/include/ $(KHDR_INCLUDES) CFLAGS += -I../

TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh \

•         rtnetlink.sh xfrm_policy.sh test_blackhole_dev.sh
  

•         rtnetlink.sh xfrm_policy.sh
  

TEST_PROGS += fib_tests.sh fib-onlink-tests.sh pmtu.sh udpgso.sh ip_defrag.sh TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh TEST_PROGS += udpgro_bench.sh udpgro.sh test_vxlan_under_vrf.sh reuseport_addr_any.sh diff --git a/tools/testing/selftests/net/test_blackhole_dev.sh b/tools/testing/selftests/net/test_blackhole_dev.sh deleted file mode 100755 index 3119b80e711f..000000000000 --- a/tools/testing/selftests/net/test_blackhole_dev.sh +++ /dev/null @@ -1,11 +0,0 @@ -#!/bin/sh -# SPDX-License-Identifier: GPL-2.0 -# Runs blackhole-dev test using blackhole-dev kernel module

-if /sbin/modprobe -q test_blackhole_dev ; then

•   /sbin/modprobe -q -r test_blackhole_dev;
  

•   echo "test_blackhole_dev: ok";
  

-else

•   echo "test_blackhole_dev: [FAIL]";
  

•   exit 1;
  

-fi

---

base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20250207-blackholedev-kunit-convert-9a52a1a1a032

Best regards,

Tamir Duberstein tamird@gmail.com

Adding David.