* [PATCH v4] lib/random32: convert selftest to KUnit
@ 2026-06-30 3:04 Kir Chou
0 siblings, 0 replies; only message in thread
From: Kir Chou @ 2026-06-30 3:04 UTC (permalink / raw)
To: akpm
Cc: thomas.weissschuh, davidgow, geert, visitorckw, brendan.higgins,
linux-kselftest, kunit-dev, Kir Chou, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman,
open list, open list:NETWORKING [GENERAL]
This patch converts the existing prandom selftest (lib/random32.c) to use
the KUnit framework (lib/tests/random32_kunit.c). Unlike typical KUnit
tests, this file is directly #included into lib/random32.c.
The new test:
- Removes the legacy CONFIG_RANDOM32_SELFTEST from lib/random32.c.
- Adds CONFIG_PRANDOM_KUNIT_TEST (defaulting to KUNIT_ALL_TESTS).
- Moves the test logic to lib/tests/random32_kunit.c.
This commit is verified by `./tools/testing/kunit/kunit.py run`
with the .kunit/.kunitconfig:
```
CONFIG_KUNIT=y
CONFIG_PRANDOM_KUNIT_TEST=y
```
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Kir Chou <note351@hotmail.com>
---
v4:
- Changes from bool to tristate in lib/Kconfig.debug.
- Spins off the test into its own module under lib/tests/.
- Adds a prototype for prandom_warmup() to avoid a warning.
- Makes prandom_warmup() visible to the test in lib/random32.c.
- Adds the build rule for random32_kunit.o to lib/tests/Makefile.
v3:
- Changes from tristate to bool in lib/Kconfig.debug.
v2:
- Removes the legacy CONFIG_RANDOM32_SELFTEST from lib/Kconfig.
- Add const to arrays in lib/tests/random32_kunit.c.
---
lib/Kconfig | 6 --
lib/Kconfig.debug | 9 ++
lib/random32.c | 184 ++-----------------------------------
lib/tests/Makefile | 1 +
lib/tests/random32_kunit.c | 181 ++++++++++++++++++++++++++++++++++++
5 files changed, 201 insertions(+), 180 deletions(-)
create mode 100644 lib/tests/random32_kunit.c
diff --git a/lib/Kconfig b/lib/Kconfig
index 2923924be..5f185e9f1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -156,12 +156,6 @@ config AUDIT_COMPAT_GENERIC
depends on AUDIT_GENERIC && AUDIT_ARCH_COMPAT_GENERIC && COMPAT
default y
-config RANDOM32_SELFTEST
- bool "PRNG perform self test on init"
- help
- This option enables the 32 bit PRNG library functions to perform a
- self test on initialization.
-
#
# compression support is select'ed if needed
#
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ba36939fd..0214a5859 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3354,6 +3354,15 @@ config PRIME_NUMBERS_KUNIT_TEST
If unsure, say N
+config PRANDOM_KUNIT_TEST
+ tristate "KUnit test for prandom" if !KUNIT_ALL_TESTS
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Enable this option to test the prandom functions at runtime.
+
+ If unsure, say N
+
endif # RUNTIME_TESTING_MENU
config ARCH_USE_MEMTEST
diff --git a/lib/random32.c b/lib/random32.c
index 24e7acd93..dad90219c 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -41,6 +41,7 @@
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/unaligned.h>
+#include <kunit/visibility.h>
/**
* prandom_u32_state - seeded pseudo-random number generator.
@@ -92,7 +93,14 @@ void prandom_bytes_state(struct rnd_state *state, void *buf, size_t bytes)
}
EXPORT_SYMBOL(prandom_bytes_state);
-static void prandom_warmup(struct rnd_state *state)
+/*
+ * Only declared here so that it has a prototype when made
+ * non-static for KUnit testing (avoids -Wmissing-prototypes).
+ */
+#if IS_ENABLED(CONFIG_KUNIT)
+void prandom_warmup(struct rnd_state *state);
+#endif
+VISIBLE_IF_KUNIT void prandom_warmup(struct rnd_state *state)
{
/* Calling RNG ten times to satisfy recurrence condition */
prandom_u32_state(state);
@@ -106,6 +114,7 @@ static void prandom_warmup(struct rnd_state *state)
prandom_u32_state(state);
prandom_u32_state(state);
}
+EXPORT_SYMBOL_IF_KUNIT(prandom_warmup);
void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state)
{
@@ -125,176 +134,3 @@ void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state)
}
}
EXPORT_SYMBOL(prandom_seed_full_state);
-
-#ifdef CONFIG_RANDOM32_SELFTEST
-static struct prandom_test1 {
- u32 seed;
- u32 result;
-} test1[] = {
- { 1U, 3484351685U },
- { 2U, 2623130059U },
- { 3U, 3125133893U },
- { 4U, 984847254U },
-};
-
-static struct prandom_test2 {
- u32 seed;
- u32 iteration;
- u32 result;
-} test2[] = {
- /* Test cases against taus113 from GSL library. */
- { 931557656U, 959U, 2975593782U },
- { 1339693295U, 876U, 3887776532U },
- { 1545556285U, 961U, 1615538833U },
- { 601730776U, 723U, 1776162651U },
- { 1027516047U, 687U, 511983079U },
- { 416526298U, 700U, 916156552U },
- { 1395522032U, 652U, 2222063676U },
- { 366221443U, 617U, 2992857763U },
- { 1539836965U, 714U, 3783265725U },
- { 556206671U, 994U, 799626459U },
- { 684907218U, 799U, 367789491U },
- { 2121230701U, 931U, 2115467001U },
- { 1668516451U, 644U, 3620590685U },
- { 768046066U, 883U, 2034077390U },
- { 1989159136U, 833U, 1195767305U },
- { 536585145U, 996U, 3577259204U },
- { 1008129373U, 642U, 1478080776U },
- { 1740775604U, 939U, 1264980372U },
- { 1967883163U, 508U, 10734624U },
- { 1923019697U, 730U, 3821419629U },
- { 442079932U, 560U, 3440032343U },
- { 1961302714U, 845U, 841962572U },
- { 2030205964U, 962U, 1325144227U },
- { 1160407529U, 507U, 240940858U },
- { 635482502U, 779U, 4200489746U },
- { 1252788931U, 699U, 867195434U },
- { 1961817131U, 719U, 668237657U },
- { 1071468216U, 983U, 917876630U },
- { 1281848367U, 932U, 1003100039U },
- { 582537119U, 780U, 1127273778U },
- { 1973672777U, 853U, 1071368872U },
- { 1896756996U, 762U, 1127851055U },
- { 847917054U, 500U, 1717499075U },
- { 1240520510U, 951U, 2849576657U },
- { 1685071682U, 567U, 1961810396U },
- { 1516232129U, 557U, 3173877U },
- { 1208118903U, 612U, 1613145022U },
- { 1817269927U, 693U, 4279122573U },
- { 1510091701U, 717U, 638191229U },
- { 365916850U, 807U, 600424314U },
- { 399324359U, 702U, 1803598116U },
- { 1318480274U, 779U, 2074237022U },
- { 697758115U, 840U, 1483639402U },
- { 1696507773U, 840U, 577415447U },
- { 2081979121U, 981U, 3041486449U },
- { 955646687U, 742U, 3846494357U },
- { 1250683506U, 749U, 836419859U },
- { 595003102U, 534U, 366794109U },
- { 47485338U, 558U, 3521120834U },
- { 619433479U, 610U, 3991783875U },
- { 704096520U, 518U, 4139493852U },
- { 1712224984U, 606U, 2393312003U },
- { 1318233152U, 922U, 3880361134U },
- { 855572992U, 761U, 1472974787U },
- { 64721421U, 703U, 683860550U },
- { 678931758U, 840U, 380616043U },
- { 692711973U, 778U, 1382361947U },
- { 677703619U, 530U, 2826914161U },
- { 92393223U, 586U, 1522128471U },
- { 1222592920U, 743U, 3466726667U },
- { 358288986U, 695U, 1091956998U },
- { 1935056945U, 958U, 514864477U },
- { 735675993U, 990U, 1294239989U },
- { 1560089402U, 897U, 2238551287U },
- { 70616361U, 829U, 22483098U },
- { 368234700U, 731U, 2913875084U },
- { 20221190U, 879U, 1564152970U },
- { 539444654U, 682U, 1835141259U },
- { 1314987297U, 840U, 1801114136U },
- { 2019295544U, 645U, 3286438930U },
- { 469023838U, 716U, 1637918202U },
- { 1843754496U, 653U, 2562092152U },
- { 400672036U, 809U, 4264212785U },
- { 404722249U, 965U, 2704116999U },
- { 600702209U, 758U, 584979986U },
- { 519953954U, 667U, 2574436237U },
- { 1658071126U, 694U, 2214569490U },
- { 420480037U, 749U, 3430010866U },
- { 690103647U, 969U, 3700758083U },
- { 1029424799U, 937U, 3787746841U },
- { 2012608669U, 506U, 3362628973U },
- { 1535432887U, 998U, 42610943U },
- { 1330635533U, 857U, 3040806504U },
- { 1223800550U, 539U, 3954229517U },
- { 1322411537U, 680U, 3223250324U },
- { 1877847898U, 945U, 2915147143U },
- { 1646356099U, 874U, 965988280U },
- { 805687536U, 744U, 4032277920U },
- { 1948093210U, 633U, 1346597684U },
- { 392609744U, 783U, 1636083295U },
- { 690241304U, 770U, 1201031298U },
- { 1360302965U, 696U, 1665394461U },
- { 1220090946U, 780U, 1316922812U },
- { 447092251U, 500U, 3438743375U },
- { 1613868791U, 592U, 828546883U },
- { 523430951U, 548U, 2552392304U },
- { 726692899U, 810U, 1656872867U },
- { 1364340021U, 836U, 3710513486U },
- { 1986257729U, 931U, 935013962U },
- { 407983964U, 921U, 728767059U },
-};
-
-static void prandom_state_selftest_seed(struct rnd_state *state, u32 seed)
-{
-#define LCG(x) ((x) * 69069U) /* super-duper LCG */
- state->s1 = __seed(LCG(seed), 2U);
- state->s2 = __seed(LCG(state->s1), 8U);
- state->s3 = __seed(LCG(state->s2), 16U);
- state->s4 = __seed(LCG(state->s3), 128U);
-}
-
-static int __init prandom_state_selftest(void)
-{
- int i, j, errors = 0, runs = 0;
- bool error = false;
-
- for (i = 0; i < ARRAY_SIZE(test1); i++) {
- struct rnd_state state;
-
- prandom_state_selftest_seed(&state, test1[i].seed);
- prandom_warmup(&state);
-
- if (test1[i].result != prandom_u32_state(&state))
- error = true;
- }
-
- if (error)
- pr_warn("prandom: seed boundary self test failed\n");
- else
- pr_info("prandom: seed boundary self test passed\n");
-
- for (i = 0; i < ARRAY_SIZE(test2); i++) {
- struct rnd_state state;
-
- prandom_state_selftest_seed(&state, test2[i].seed);
- prandom_warmup(&state);
-
- for (j = 0; j < test2[i].iteration - 1; j++)
- prandom_u32_state(&state);
-
- if (test2[i].result != prandom_u32_state(&state))
- errors++;
-
- runs++;
- cond_resched();
- }
-
- if (errors)
- pr_warn("prandom: %d/%d self tests failed\n", errors, runs);
- else
- pr_info("prandom: %d self tests passed\n", runs);
- return 0;
-}
-core_initcall(prandom_state_selftest);
-#endif
diff --git a/lib/tests/Makefile b/lib/tests/Makefile
index 601dba4b7..39d283b26 100644
--- a/lib/tests/Makefile
+++ b/lib/tests/Makefile
@@ -49,5 +49,6 @@ obj-$(CONFIG_STRING_HELPERS_KUNIT_TEST) += string_helpers_kunit.o
obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o
obj-$(CONFIG_UTIL_MACROS_KUNIT) += util_macros_kunit.o
obj-$(CONFIG_RATELIMIT_KUNIT_TEST) += test_ratelimit.o
+obj-$(CONFIG_PRANDOM_KUNIT_TEST) += random32_kunit.o
obj-$(CONFIG_TEST_RUNTIME_MODULE) += module/
diff --git a/lib/tests/random32_kunit.c b/lib/tests/random32_kunit.c
new file mode 100644
index 000000000..436435026
--- /dev/null
+++ b/lib/tests/random32_kunit.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test cases for random32 functions.
+ */
+
+#include <linux/prandom.h>
+#include <kunit/test.h>
+
+/* prandom_warmup() is static in lib/random32.c; exposed for testing only. */
+void prandom_warmup(struct rnd_state *state);
+
+static const struct prandom_test1 {
+ u32 seed;
+ u32 result;
+} test1[] = {
+ { 1U, 3484351685U },
+ { 2U, 2623130059U },
+ { 3U, 3125133893U },
+ { 4U, 984847254U },
+};
+
+static const struct prandom_test2 {
+ u32 seed;
+ u32 iteration;
+ u32 result;
+} test2[] = {
+ /* Test cases against taus113 from GSL library. */
+ { 931557656U, 959U, 2975593782U },
+ { 1339693295U, 876U, 3887776532U },
+ { 1545556285U, 961U, 1615538833U },
+ { 601730776U, 723U, 1776162651U },
+ { 1027516047U, 687U, 511983079U },
+ { 416526298U, 700U, 916156552U },
+ { 1395522032U, 652U, 2222063676U },
+ { 366221443U, 617U, 2992857763U },
+ { 1539836965U, 714U, 3783265725U },
+ { 556206671U, 994U, 799626459U },
+ { 684907218U, 799U, 367789491U },
+ { 2121230701U, 931U, 2115467001U },
+ { 1668516451U, 644U, 3620590685U },
+ { 768046066U, 883U, 2034077390U },
+ { 1989159136U, 833U, 1195767305U },
+ { 536585145U, 996U, 3577259204U },
+ { 1008129373U, 642U, 1478080776U },
+ { 1740775604U, 939U, 1264980372U },
+ { 1967883163U, 508U, 10734624U },
+ { 1923019697U, 730U, 3821419629U },
+ { 442079932U, 560U, 3440032343U },
+ { 1961302714U, 845U, 841962572U },
+ { 2030205964U, 962U, 1325144227U },
+ { 1160407529U, 507U, 240940858U },
+ { 635482502U, 779U, 4200489746U },
+ { 1252788931U, 699U, 867195434U },
+ { 1961817131U, 719U, 668237657U },
+ { 1071468216U, 983U, 917876630U },
+ { 1281848367U, 932U, 1003100039U },
+ { 582537119U, 780U, 1127273778U },
+ { 1973672777U, 853U, 1071368872U },
+ { 1896756996U, 762U, 1127851055U },
+ { 847917054U, 500U, 1717499075U },
+ { 1240520510U, 951U, 2849576657U },
+ { 1685071682U, 567U, 1961810396U },
+ { 1516232129U, 557U, 3173877U },
+ { 1208118903U, 612U, 1613145022U },
+ { 1817269927U, 693U, 4279122573U },
+ { 1510091701U, 717U, 638191229U },
+ { 365916850U, 807U, 600424314U },
+ { 399324359U, 702U, 1803598116U },
+ { 1318480274U, 779U, 2074237022U },
+ { 697758115U, 840U, 1483639402U },
+ { 1696507773U, 840U, 577415447U },
+ { 2081979121U, 981U, 3041486449U },
+ { 955646687U, 742U, 3846494357U },
+ { 1250683506U, 749U, 836419859U },
+ { 595003102U, 534U, 366794109U },
+ { 47485338U, 558U, 3521120834U },
+ { 619433479U, 610U, 3991783875U },
+ { 704096520U, 518U, 4139493852U },
+ { 1712224984U, 606U, 2393312003U },
+ { 1318233152U, 922U, 3880361134U },
+ { 855572992U, 761U, 1472974787U },
+ { 64721421U, 703U, 683860550U },
+ { 678931758U, 840U, 380616043U },
+ { 692711973U, 778U, 1382361947U },
+ { 677703619U, 530U, 2826914161U },
+ { 92393223U, 586U, 1522128471U },
+ { 1222592920U, 743U, 3466726667U },
+ { 358288986U, 695U, 1091956998U },
+ { 1935056945U, 958U, 514864477U },
+ { 735675993U, 990U, 1294239989U },
+ { 1560089402U, 897U, 2238551287U },
+ { 70616361U, 829U, 22483098U },
+ { 368234700U, 731U, 2913875084U },
+ { 20221190U, 879U, 1564152970U },
+ { 539444654U, 682U, 1835141259U },
+ { 1314987297U, 840U, 1801114136U },
+ { 2019295544U, 645U, 3286438930U },
+ { 469023838U, 716U, 1637918202U },
+ { 1843754496U, 653U, 2562092152U },
+ { 400672036U, 809U, 4264212785U },
+ { 404722249U, 965U, 2704116999U },
+ { 600702209U, 758U, 584979986U },
+ { 519953954U, 667U, 2574436237U },
+ { 1658071126U, 694U, 2214569490U },
+ { 420480037U, 749U, 3430010866U },
+ { 690103647U, 969U, 3700758083U },
+ { 1029424799U, 937U, 3787746841U },
+ { 2012608669U, 506U, 3362628973U },
+ { 1535432887U, 998U, 42610943U },
+ { 1330635533U, 857U, 3040806504U },
+ { 1223800550U, 539U, 3954229517U },
+ { 1322411537U, 680U, 3223250324U },
+ { 1877847898U, 945U, 2915147143U },
+ { 1646356099U, 874U, 965988280U },
+ { 805687536U, 744U, 4032277920U },
+ { 1948093210U, 633U, 1346597684U },
+ { 392609744U, 783U, 1636083295U },
+ { 690241304U, 770U, 1201031298U },
+ { 1360302965U, 696U, 1665394461U },
+ { 1220090946U, 780U, 1316922812U },
+ { 447092251U, 500U, 3438743375U },
+ { 1613868791U, 592U, 828546883U },
+ { 523430951U, 548U, 2552392304U },
+ { 726692899U, 810U, 1656872867U },
+ { 1364340021U, 836U, 3710513486U },
+ { 1986257729U, 931U, 935013962U },
+ { 407983964U, 921U, 728767059U },
+};
+
+static void prandom_state_test_seed(struct rnd_state *state, u32 seed)
+{
+#define LCG(x) ((x) * 69069U) /* super-duper LCG */
+ state->s1 = __seed(LCG(seed), 2U);
+ state->s2 = __seed(LCG(state->s1), 8U);
+ state->s3 = __seed(LCG(state->s2), 16U);
+ state->s4 = __seed(LCG(state->s3), 128U);
+}
+
+static void test_prandom_seed_boundary(struct kunit *test)
+{
+ int i;
+ struct rnd_state state;
+
+ for (i = 0; i < ARRAY_SIZE(test1); i++) {
+ prandom_state_test_seed(&state, test1[i].seed);
+ prandom_warmup(&state);
+ KUNIT_EXPECT_EQ(test, test1[i].result, prandom_u32_state(&state));
+ }
+}
+
+static void test_prandom_taus113(struct kunit *test)
+{
+ int i, j;
+ struct rnd_state state;
+
+ for (i = 0; i < ARRAY_SIZE(test2); i++) {
+ prandom_state_test_seed(&state, test2[i].seed);
+ prandom_warmup(&state);
+
+ for (j = 0; j < test2[i].iteration - 1; j++)
+ prandom_u32_state(&state);
+
+ KUNIT_EXPECT_EQ(test, test2[i].result, prandom_u32_state(&state));
+ }
+}
+
+static struct kunit_case prandom_test_cases[] = {
+ KUNIT_CASE(test_prandom_seed_boundary),
+ KUNIT_CASE(test_prandom_taus113),
+ {}
+};
+
+static struct kunit_suite prandom_test_suite = {
+ .name = "prandom",
+ .test_cases = prandom_test_cases,
+};
+
+kunit_test_suite(prandom_test_suite);
+
+MODULE_DESCRIPTION("KUnit test for prandom");
+MODULE_LICENSE("GPL");
--
2.52.0
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