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selftests/bpf: Make seen_tc* variable tests more robust
jira LE-1907 Rebuild_History Non-Buildable kernel-5.14.0-427.18.1.el9_4 commit-author Daniel Borkmann <[email protected]> commit 37345b8 Martin reported that on his local dev machine the test_tc_chain_mixed() fails as "test_tc_chain_mixed:FAIL:seen_tc5 unexpected seen_tc5: actual 1 != expected 0" and others occasionally, too. However, when running in a more isolated setup (qemu in particular), it works fine for him. The reason is that there is a small race-window where seen_tc* could turn into true for various test cases when there is background traffic, e.g. after the asserts they often get reset. In such case when subsequent detach takes place, unrelated background traffic could have already flipped the bool to true beforehand. Add a small helper tc_skel_reset_all_seen() to reset all bools before we do the ping test. At this point, everything is set up as expected and therefore no race can occur. All tc_{opts,links} tests continue to pass after this change. Reported-by: Martin KaFai Lau <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Martin KaFai Lau <[email protected]> (cherry picked from commit 37345b8) Signed-off-by: Jonathan Maple <[email protected]>
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3 files changed

+46
-60
lines changed

‎tools/testing/selftests/bpf/prog_tests/tc_helpers.h‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -66,4 +66,9 @@ static inline void assert_mprog_count_ifindex(int ifindex, int target, int expec
6666
__assert_mprog_count(target, expected, ifindex);
6767
}
6868

69+
static inline void tc_skel_reset_all_seen(struct test_tc_link *skel)
70+
{
71+
memset(skel->bss, 0, sizeof(*skel->bss));
72+
}
73+
6974
#endif /* TC_HELPERS */

‎tools/testing/selftests/bpf/prog_tests/tc_links.c‎

Lines changed: 22 additions & 40 deletions
Original file line numberDiff line numberDiff line change
@@ -65,6 +65,7 @@ void serial_test_tc_links_basic(void)
6565
ASSERT_EQ(optq.prog_ids[1], 0, "prog_ids[1]");
6666
ASSERT_EQ(optq.link_ids[1], 0, "link_ids[1]");
6767

68+
tc_skel_reset_all_seen(skel);
6869
ASSERT_OK(system(ping_cmd), ping_cmd);
6970

7071
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -97,6 +98,7 @@ void serial_test_tc_links_basic(void)
9798
ASSERT_EQ(optq.prog_ids[1], 0, "prog_ids[1]");
9899
ASSERT_EQ(optq.link_ids[1], 0, "link_ids[1]");
99100

101+
tc_skel_reset_all_seen(skel);
100102
ASSERT_OK(system(ping_cmd), ping_cmd);
101103

102104
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -187,16 +189,14 @@ static void test_tc_links_before_target(int target)
187189
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
188190
ASSERT_EQ(optq.link_ids[2], 0, "link_ids[2]");
189191

192+
tc_skel_reset_all_seen(skel);
190193
ASSERT_OK(system(ping_cmd), ping_cmd);
191194

192195
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
193196
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
194197
ASSERT_EQ(skel->bss->seen_tc3, false, "seen_tc3");
195198
ASSERT_EQ(skel->bss->seen_tc4, false, "seen_tc4");
196199

197-
skel->bss->seen_tc1 = false;
198-
skel->bss->seen_tc2 = false;
199-
200200
LIBBPF_OPTS_RESET(optl,
201201
.flags = BPF_F_BEFORE,
202202
.relative_fd = bpf_program__fd(skel->progs.tc2),
@@ -246,6 +246,7 @@ static void test_tc_links_before_target(int target)
246246
ASSERT_EQ(optq.prog_ids[4], 0, "prog_ids[4]");
247247
ASSERT_EQ(optq.link_ids[4], 0, "link_ids[4]");
248248

249+
tc_skel_reset_all_seen(skel);
249250
ASSERT_OK(system(ping_cmd), ping_cmd);
250251

251252
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -342,16 +343,14 @@ static void test_tc_links_after_target(int target)
342343
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
343344
ASSERT_EQ(optq.link_ids[2], 0, "link_ids[2]");
344345

346+
tc_skel_reset_all_seen(skel);
345347
ASSERT_OK(system(ping_cmd), ping_cmd);
346348

347349
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
348350
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
349351
ASSERT_EQ(skel->bss->seen_tc3, false, "seen_tc3");
350352
ASSERT_EQ(skel->bss->seen_tc4, false, "seen_tc4");
351353

352-
skel->bss->seen_tc1 = false;
353-
skel->bss->seen_tc2 = false;
354-
355354
LIBBPF_OPTS_RESET(optl,
356355
.flags = BPF_F_AFTER,
357356
.relative_fd = bpf_program__fd(skel->progs.tc1),
@@ -401,6 +400,7 @@ static void test_tc_links_after_target(int target)
401400
ASSERT_EQ(optq.prog_ids[4], 0, "prog_ids[4]");
402401
ASSERT_EQ(optq.link_ids[4], 0, "link_ids[4]");
403402

403+
tc_skel_reset_all_seen(skel);
404404
ASSERT_OK(system(ping_cmd), ping_cmd);
405405

406406
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -502,6 +502,7 @@ static void test_tc_links_revision_target(int target)
502502
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
503503
ASSERT_EQ(optq.link_ids[2], 0, "prog_ids[2]");
504504

505+
tc_skel_reset_all_seen(skel);
505506
ASSERT_OK(system(ping_cmd), ping_cmd);
506507

507508
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -581,22 +582,20 @@ static void test_tc_chain_classic(int target, bool chain_tc_old)
581582

582583
assert_mprog_count(target, 2);
583584

585+
tc_skel_reset_all_seen(skel);
584586
ASSERT_OK(system(ping_cmd), ping_cmd);
585587

586588
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
587589
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
588590
ASSERT_EQ(skel->bss->seen_tc3, chain_tc_old, "seen_tc3");
589591

590-
skel->bss->seen_tc1 = false;
591-
skel->bss->seen_tc2 = false;
592-
skel->bss->seen_tc3 = false;
593-
594592
err = bpf_link__detach(skel->links.tc2);
595593
if (!ASSERT_OK(err, "prog_detach"))
596594
goto cleanup;
597595

598596
assert_mprog_count(target, 1);
599597

598+
tc_skel_reset_all_seen(skel);
600599
ASSERT_OK(system(ping_cmd), ping_cmd);
601600

602601
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -707,16 +706,13 @@ static void test_tc_links_replace_target(int target)
707706
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
708707
ASSERT_EQ(optq.link_ids[2], 0, "link_ids[2]");
709708

709+
tc_skel_reset_all_seen(skel);
710710
ASSERT_OK(system(ping_cmd), ping_cmd);
711711

712712
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
713713
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
714714
ASSERT_EQ(skel->bss->seen_tc3, false, "seen_tc3");
715715

716-
skel->bss->seen_tc1 = false;
717-
skel->bss->seen_tc2 = false;
718-
skel->bss->seen_tc3 = false;
719-
720716
LIBBPF_OPTS_RESET(optl,
721717
.flags = BPF_F_REPLACE,
722718
.relative_fd = bpf_program__fd(skel->progs.tc2),
@@ -781,16 +777,13 @@ static void test_tc_links_replace_target(int target)
781777
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
782778
ASSERT_EQ(optq.link_ids[2], 0, "link_ids[2]");
783779

780+
tc_skel_reset_all_seen(skel);
784781
ASSERT_OK(system(ping_cmd), ping_cmd);
785782

786783
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
787784
ASSERT_EQ(skel->bss->seen_tc2, false, "seen_tc2");
788785
ASSERT_EQ(skel->bss->seen_tc3, true, "seen_tc3");
789786

790-
skel->bss->seen_tc1 = false;
791-
skel->bss->seen_tc2 = false;
792-
skel->bss->seen_tc3 = false;
793-
794787
err = bpf_link__detach(skel->links.tc2);
795788
if (!ASSERT_OK(err, "link_detach"))
796789
goto cleanup;
@@ -812,16 +805,13 @@ static void test_tc_links_replace_target(int target)
812805
ASSERT_EQ(optq.prog_ids[1], 0, "prog_ids[1]");
813806
ASSERT_EQ(optq.link_ids[1], 0, "link_ids[1]");
814807

808+
tc_skel_reset_all_seen(skel);
815809
ASSERT_OK(system(ping_cmd), ping_cmd);
816810

817811
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
818812
ASSERT_EQ(skel->bss->seen_tc2, false, "seen_tc2");
819813
ASSERT_EQ(skel->bss->seen_tc3, false, "seen_tc3");
820814

821-
skel->bss->seen_tc1 = false;
822-
skel->bss->seen_tc2 = false;
823-
skel->bss->seen_tc3 = false;
824-
825815
err = bpf_link__update_program(skel->links.tc1, skel->progs.tc1);
826816
if (!ASSERT_OK(err, "link_update_self"))
827817
goto cleanup;
@@ -843,6 +833,7 @@ static void test_tc_links_replace_target(int target)
843833
ASSERT_EQ(optq.prog_ids[1], 0, "prog_ids[1]");
844834
ASSERT_EQ(optq.link_ids[1], 0, "link_ids[1]");
845835

836+
tc_skel_reset_all_seen(skel);
846837
ASSERT_OK(system(ping_cmd), ping_cmd);
847838

848839
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -1254,16 +1245,14 @@ static void test_tc_links_prepend_target(int target)
12541245
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
12551246
ASSERT_EQ(optq.link_ids[2], 0, "link_ids[2]");
12561247

1248+
tc_skel_reset_all_seen(skel);
12571249
ASSERT_OK(system(ping_cmd), ping_cmd);
12581250

12591251
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
12601252
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
12611253
ASSERT_EQ(skel->bss->seen_tc3, false, "seen_tc3");
12621254
ASSERT_EQ(skel->bss->seen_tc4, false, "seen_tc4");
12631255

1264-
skel->bss->seen_tc1 = false;
1265-
skel->bss->seen_tc2 = false;
1266-
12671256
LIBBPF_OPTS_RESET(optl,
12681257
.flags = BPF_F_BEFORE,
12691258
);
@@ -1311,6 +1300,7 @@ static void test_tc_links_prepend_target(int target)
13111300
ASSERT_EQ(optq.prog_ids[4], 0, "prog_ids[4]");
13121301
ASSERT_EQ(optq.link_ids[4], 0, "link_ids[4]");
13131302

1303+
tc_skel_reset_all_seen(skel);
13141304
ASSERT_OK(system(ping_cmd), ping_cmd);
13151305

13161306
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -1411,16 +1401,14 @@ static void test_tc_links_append_target(int target)
14111401
ASSERT_EQ(optq.prog_ids[2], 0, "prog_ids[2]");
14121402
ASSERT_EQ(optq.link_ids[2], 0, "link_ids[2]");
14131403

1404+
tc_skel_reset_all_seen(skel);
14141405
ASSERT_OK(system(ping_cmd), ping_cmd);
14151406

14161407
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
14171408
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
14181409
ASSERT_EQ(skel->bss->seen_tc3, false, "seen_tc3");
14191410
ASSERT_EQ(skel->bss->seen_tc4, false, "seen_tc4");
14201411

1421-
skel->bss->seen_tc1 = false;
1422-
skel->bss->seen_tc2 = false;
1423-
14241412
LIBBPF_OPTS_RESET(optl,
14251413
.flags = BPF_F_AFTER,
14261414
);
@@ -1468,6 +1456,7 @@ static void test_tc_links_append_target(int target)
14681456
ASSERT_EQ(optq.prog_ids[4], 0, "prog_ids[4]");
14691457
ASSERT_EQ(optq.link_ids[4], 0, "link_ids[4]");
14701458

1459+
tc_skel_reset_all_seen(skel);
14711460
ASSERT_OK(system(ping_cmd), ping_cmd);
14721461

14731462
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
@@ -1637,38 +1626,33 @@ static void test_tc_chain_mixed(int target)
16371626

16381627
assert_mprog_count(target, 1);
16391628

1629+
tc_skel_reset_all_seen(skel);
16401630
ASSERT_OK(system(ping_cmd), ping_cmd);
16411631

16421632
ASSERT_EQ(skel->bss->seen_tc4, false, "seen_tc4");
16431633
ASSERT_EQ(skel->bss->seen_tc5, false, "seen_tc5");
16441634
ASSERT_EQ(skel->bss->seen_tc6, true, "seen_tc6");
16451635

1646-
skel->bss->seen_tc4 = false;
1647-
skel->bss->seen_tc5 = false;
1648-
skel->bss->seen_tc6 = false;
1649-
16501636
err = bpf_link__update_program(skel->links.tc6, skel->progs.tc4);
16511637
if (!ASSERT_OK(err, "link_update"))
16521638
goto cleanup;
16531639

16541640
assert_mprog_count(target, 1);
16551641

1642+
tc_skel_reset_all_seen(skel);
16561643
ASSERT_OK(system(ping_cmd), ping_cmd);
16571644

16581645
ASSERT_EQ(skel->bss->seen_tc4, true, "seen_tc4");
16591646
ASSERT_EQ(skel->bss->seen_tc5, true, "seen_tc5");
16601647
ASSERT_EQ(skel->bss->seen_tc6, false, "seen_tc6");
16611648

1662-
skel->bss->seen_tc4 = false;
1663-
skel->bss->seen_tc5 = false;
1664-
skel->bss->seen_tc6 = false;
1665-
16661649
err = bpf_link__detach(skel->links.tc6);
16671650
if (!ASSERT_OK(err, "prog_detach"))
16681651
goto cleanup;
16691652

16701653
assert_mprog_count(target, 0);
16711654

1655+
tc_skel_reset_all_seen(skel);
16721656
ASSERT_OK(system(ping_cmd), ping_cmd);
16731657

16741658
ASSERT_EQ(skel->bss->seen_tc4, false, "seen_tc4");
@@ -1758,22 +1742,20 @@ static void test_tc_links_ingress(int target, bool chain_tc_old,
17581742

17591743
assert_mprog_count(target, 2);
17601744

1745+
tc_skel_reset_all_seen(skel);
17611746
ASSERT_OK(system(ping_cmd), ping_cmd);
17621747

17631748
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");
17641749
ASSERT_EQ(skel->bss->seen_tc2, true, "seen_tc2");
17651750
ASSERT_EQ(skel->bss->seen_tc3, chain_tc_old, "seen_tc3");
17661751

1767-
skel->bss->seen_tc1 = false;
1768-
skel->bss->seen_tc2 = false;
1769-
skel->bss->seen_tc3 = false;
1770-
17711752
err = bpf_link__detach(skel->links.tc2);
17721753
if (!ASSERT_OK(err, "prog_detach"))
17731754
goto cleanup;
17741755

17751756
assert_mprog_count(target, 1);
17761757

1758+
tc_skel_reset_all_seen(skel);
17771759
ASSERT_OK(system(ping_cmd), ping_cmd);
17781760

17791761
ASSERT_EQ(skel->bss->seen_tc1, true, "seen_tc1");

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