cpumask: fix invalid uniprocessor assumptions

On uniprocessor builds, it is currently assumed that any cpumask will contain the single CPU: cpu0. This assumption is used to provide optimised implementations.

The current assumption also appears to be wrong, by ignoring the fact that users can provide empty cpumasks. This can result in bugs as explained in [1] - for_each_cpu() will run one iteration of the loop even when passed an empty cpumask.

This series introduces some basic tests, and updates the optimisations for uniprocessor builds.

The x86 patch was written after the kernel test robot [2] ran into a failed build. I have tried to list the files potentially affected by the changes to cpumask.h, in an attempt to find any other cases that fail on !SMP. I've gone through some of the files manually, and ran a few cross builds, but nothing else popped up. I (build) checked about half of the potientally affected files, but I do not have the resources to do them all. I hope we can fix other issues if/when they pop up later.

[1] https://lore.kernel.org/all/[email protected]/
[2] https://lore.kernel.org/all/[email protected]/

Quoted 20 lines · Sander Vanheule

On uniprocessor builds, it is currently assumed that any cpumask will contain the single CPU: cpu0. This assumption is used to provide optimised implementations.

The current assumption also appears to be wrong, by ignoring the fact that users can provide empty cpumasks. This can result in bugs as explained in [1] - for_each_cpu() will run one iteration of the loop even when passed an empty cpumask.

This series introduces some basic tests, and updates the optimisations for uniprocessor builds.

The x86 patch was written after the kernel test robot [2] ran into a failed build. I have tried to list the files potentially affected by the changes to cpumask.h, in an attempt to find any other cases that fail on !SMP. I've gone through some of the files manually, and ran a few cross builds, but nothing else popped up. I (build) checked about half of the potientally affected files, but I do not have the resources to do them all. I hope we can fix other issues if/when they pop up later.

Quoted 2 lines

[1] https://lore.kernel.org/all/[email protected]/
[2] https://lore.kernel.org/all/[email protected]/

Hi Sander,

I tried to apply it on top of bitmap-for next, and there are many conflicts with already pulled patches. There's nothing really scary, just functions changed their prototypes and locations. Can you try your series on top of bitmap-for-next from [email protected]:/norov/linux.git (or just -next)?

I'm asking you to do it instead of doing myself because I don't want to screwup your code accidentally and because many cpumask functions in -next are moved to the header, and it would be probably possible to avoid building cpumask.o in UP case.

Briefly looking into the -next code, cpumask.c hosts  only cpumask_next_wrap() that is not overwritten by UP code, and in UP case it can be simplified.

lib/cpumask_test.c new file +147 -0

@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KUnit tests for cpumask.
+ *
+ * Author: Sander Vanheule <[email protected]>
+ */
+
+#include <kunit/test.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+
+#define EXPECT_FOR_EACH_CPU_EQ(test, mask)			\
+	do {							\
+		const cpumask_t *m = (mask);			\
+		int mask_weight = cpumask_weight(m);		\
+		int cpu, iter = 0;				\
+		for_each_cpu(cpu, m)				\
+			iter++;					\
+		KUNIT_EXPECT_EQ((test), mask_weight, iter);	\
+	} while (0)
+
+#define EXPECT_FOR_EACH_CPU_NOT_EQ(test, mask)					\
+	do {									\
+		const cpumask_t *m = (mask);					\
+		int mask_weight = cpumask_weight(m);				\
+		int cpu, iter = 0;						\
+		for_each_cpu_not(cpu, m)					\
+			iter++;							\
+		KUNIT_EXPECT_EQ((test), nr_cpu_ids - mask_weight, iter);	\
+	} while (0)
+
+#define EXPECT_FOR_EACH_CPU_WRAP_EQ(test, mask)			\
+	do {							\
+		const cpumask_t *m = (mask);			\
+		int mask_weight = cpumask_weight(m);		\
+		int cpu, iter = 0;				\
+		for_each_cpu_wrap(cpu, m, nr_cpu_ids / 2)	\
+			iter++;					\
+		KUNIT_EXPECT_EQ((test), mask_weight, iter);	\
+	} while (0)
+
+#define EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, name)		\
+	do {							\
+		int mask_weight = num_##name##_cpus();		\
+		int cpu, iter = 0;				\
+		for_each_##name##_cpu(cpu)			\
+			iter++;					\
+		KUNIT_EXPECT_EQ((test), mask_weight, iter);	\
+	} while (0)
+
+static cpumask_t mask_empty;
+static cpumask_t mask_all;
+
+#define STR_MASK(m)			#m
+#define TEST_CPUMASK_PRINT(test, mask)	\
+	kunit_info(test, "%s = '%*pbl'\n", STR_MASK(mask), nr_cpumask_bits, cpumask_bits(mask))
+
+static void test_cpumask_weight(struct kunit *test)
+{
+	KUNIT_EXPECT_TRUE(test, cpumask_empty(&mask_empty));
+	KUNIT_EXPECT_TRUE(test, cpumask_full(&mask_all));
+
+	KUNIT_EXPECT_EQ(test, 0, cpumask_weight(&mask_empty));
+	KUNIT_EXPECT_EQ(test, nr_cpu_ids, cpumask_weight(cpu_possible_mask));
+	KUNIT_EXPECT_EQ(test, nr_cpumask_bits, cpumask_weight(&mask_all));
+}
+
+static void test_cpumask_first(struct kunit *test)
+{
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_first(&mask_empty));
+	KUNIT_EXPECT_EQ(test, 0, cpumask_first(cpu_possible_mask));
+
+	KUNIT_EXPECT_EQ(test, 0, cpumask_first_zero(&mask_empty));
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_first_zero(cpu_possible_mask));
+}
+
+static void test_cpumask_last(struct kunit *test)
+{
+	KUNIT_EXPECT_LE(test, nr_cpumask_bits, cpumask_last(&mask_empty));
+	KUNIT_EXPECT_EQ(test, nr_cpu_ids - 1, cpumask_last(cpu_possible_mask));
+}
+
+static void test_cpumask_next(struct kunit *test)
+{
+	KUNIT_EXPECT_EQ(test, 0, cpumask_next_zero(-1, &mask_empty));
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_next_zero(-1, cpu_possible_mask));
+
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_next(-1, &mask_empty));
+	KUNIT_EXPECT_EQ(test, 0, cpumask_next(-1, cpu_possible_mask));
+}
+
+static void test_cpumask_iterators(struct kunit *test)
+{
+	EXPECT_FOR_EACH_CPU_EQ(test, &mask_empty);
+	EXPECT_FOR_EACH_CPU_NOT_EQ(test, &mask_empty);
+	EXPECT_FOR_EACH_CPU_WRAP_EQ(test, &mask_empty);
+
+	EXPECT_FOR_EACH_CPU_EQ(test, cpu_possible_mask);
+	EXPECT_FOR_EACH_CPU_NOT_EQ(test, cpu_possible_mask);
+	EXPECT_FOR_EACH_CPU_WRAP_EQ(test, cpu_possible_mask);
+}
+
+static void test_cpumask_iterators_builtin(struct kunit *test)
+{
+	EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, possible);
+
+	/* Ensure the dynamic masks are stable while running the tests */
+	cpu_hotplug_disable();
+
+	TEST_CPUMASK_PRINT(test, cpu_online_mask);
+	TEST_CPUMASK_PRINT(test, cpu_present_mask);
+
+	EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, online);
+	EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, present);
+
+	cpu_hotplug_enable();
+}
+
+static int test_cpumask_init(struct kunit *test)
+{
+	cpumask_clear(&mask_empty);
+	cpumask_setall(&mask_all);
+
+	TEST_CPUMASK_PRINT(test, &mask_all);
+	TEST_CPUMASK_PRINT(test, cpu_possible_mask);
+
+	return 0;
+}
+
+static struct kunit_case test_cpumask_cases[] = {
+	KUNIT_CASE(test_cpumask_weight),
+	KUNIT_CASE(test_cpumask_first),
+	KUNIT_CASE(test_cpumask_last),
+	KUNIT_CASE(test_cpumask_next),
+	KUNIT_CASE(test_cpumask_iterators),
+	KUNIT_CASE(test_cpumask_iterators_builtin),
+	{}
+};
+
+static struct kunit_suite test_cpumask_suite = {
+	.name = "cpumask",
+	.init = test_cpumask_init,
+	.test_cases = test_cpumask_cases,
+};
+kunit_test_suite(test_cpumask_suite);
+
+MODULE_LICENSE("GPL");

Quoted 36 lines · Yury Norov

Quoted 20 lines · Sander Vanheule

On uniprocessor builds, it is currently assumed that any cpumask will contain the single CPU: cpu0. This assumption is used to provide optimised implementations.

The current assumption also appears to be wrong, by ignoring the fact that users can provide empty cpumasks. This can result in bugs as explained in [1] - for_each_cpu() will run one iteration of the loop even when passed an empty cpumask.

This series introduces some basic tests, and updates the optimisations for uniprocessor builds.

The x86 patch was written after the kernel test robot [2] ran into a failed build. I have tried to list the files potentially affected by the changes to cpumask.h, in an attempt to find any other cases that fail on !SMP. I've gone through some of the files manually, and ran a few cross builds, but nothing else popped up. I (build) checked about half of the potientally affected files, but I do not have the resources to do them all. I hope we can fix other issues if/when they pop up later.

Quoted 2 lines

[1] https://lore.kernel.org/all/[email protected]/
[2] https://lore.kernel.org/all/[email protected]/

Hi Sander,

I tried to apply it on top of bitmap-for next, and there are many conflicts with already pulled patches. There's nothing really scary, just functions changed their prototypes and locations. Can you try your series on top of bitmap-for-next from [email protected]:/norov/linux.git (or just -next)?

I'm asking you to do it instead of doing myself because I don't want to screwup your code accidentally and because many cpumask functions in -next are moved to the header, and it would be probably possible to avoid building cpumask.o in UP case.

Quoted 2 lines

Briefly looking into the -next code, cpumask.c hosts  only cpumask_next_wrap() that is not overwritten by UP code, and in UP case it can be simplified.

Sure. I've rebased my patches and added a UP-version for cpumask_next_wrap(), so cpumask.o doesn't have to be built anymore in that case.

How would you like to proceed with these patches? It's fine by me if you take them through your tree to avoid more merge conflicts with your changes, but then Andrew woud have to drop the series from mm-nonmm-stable.

Hi Sander

Quoted 82 lines · Sander Vanheule

Add a basic suite of tests for cpumask, providing some tests for empty and completely filled cpumasks.

Signed-off-by Sander Vanheule <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

Suggested-by Yury Norov <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Dave Hansen <[email protected]>

Cc Greg Kroah-Hartman <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Marco Elver <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Valentin Schneider <[email protected]>

Cc Brendan Higgins <[email protected]>

Cc David Gow <[email protected]>

Cc Maíra Canal <[email protected]>

---
Changes since v4:
- Belated addition of Yury's Suggested-by:
- Follow KUnit style more closely
- Drop full check on cpu_possible_mask
- Update last check on cpu_possible_mask
- Log masks when starting test
- Update commit message

Changes since v3:
- Test for_each_cpu*() over empty mask and cpu_possible_mask
- Add Andy's Reviewed-by
- Use num_{online,present,possible}_cpus() for builtin masks
- Guard against CPU hotplugging during test for dynamic builtin CPU masks
Changes since v2:
- Rework for_each_* test macros, as suggested by Yury

Changes since v1:
- New patch

 lib/Kconfig.debug  |  12 ++++
 lib/Makefile       |   1 +
 lib/cpumask_test.c | 147 +++++++++++++++++++++++++++++++++++++++++++++

 3 files changed, 160 insertions(+)

 create mode 100644 lib/cpumask_test.c

lib/Kconfig.debug +0 -0

index 2e24db4bff19..e85e74646178 100644
@@ -2021,6 +2021,18 @@ config LKDTM

        Documentation on how to use the module can be found in Documentation/fault-injection/provoke-crashes.rst

+config CPUMASK_KUNIT_TEST
+       tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS +       depends on KUNIT
+       default KUNIT_ALL_TESTS
+       help
+         Enable to turn on cpumask tests, running at boot or module load time.
+
+         For more information on KUnit and unit tests in general, please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.

lib/Kconfig.debug +3 -0

+
+         If unsure, say N.
+

 config TEST_LIST_SORT
        tristate "Linked list sorting test" if !KUNIT_ALL_TESTS depends on KUNIT

lib/Makefile +0 -0

index bcc7e8ea0cde..9f9db1376538 100644
@@ -59,6 +59,7 @@ obj-$(CONFIG_TEST_BPF) += test_bpf.o

 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o obj-$(CONFIG_TEST_BITOPS) += test_bitops.o CFLAGS_test_bitops.o += -Werror +obj-$(CONFIG_CPUMASK_KUNIT_TEST) += cpumask_test.o obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o obj-$(CONFIG_TEST_SIPHASH) += test_siphash.o obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o

lib/cpumask_test.c

Quoted 5 lines

lib/cpumask_test.c new file +0 -0

new file mode 100644
index 000000000000..0f8059a5e93b

In order to make the tests at lib/ with more compliant naming, it would make more sense to name it test_cpumask.c.

Thank you for the respin to the series! All tests are passing now.

Tested-by Maíra Canal <[email protected]>

Quoted 85 lines · Maíra Canal

Hi Sander

Quoted 82 lines · Sander Vanheule

Add a basic suite of tests for cpumask, providing some tests for empty and completely filled cpumasks.

Signed-off-by Sander Vanheule <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

Suggested-by Yury Norov <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Dave Hansen <[email protected]>

Cc Greg Kroah-Hartman <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Marco Elver <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Valentin Schneider <[email protected]>

Cc Brendan Higgins <[email protected]>

Cc David Gow <[email protected]>

Cc Maíra Canal <[email protected]>

---
Changes since v4:
- Belated addition of Yury's Suggested-by:
- Follow KUnit style more closely
- Drop full check on cpu_possible_mask
- Update last check on cpu_possible_mask
- Log masks when starting test
- Update commit message

Changes since v3:
- Test for_each_cpu*() over empty mask and cpu_possible_mask
- Add Andy's Reviewed-by
- Use num_{online,present,possible}_cpus() for builtin masks
- Guard against CPU hotplugging during test for dynamic builtin CPU masks
Changes since v2:
- Rework for_each_* test macros, as suggested by Yury

Changes since v1:
- New patch

 lib/Kconfig.debug  |  12 ++++
 lib/Makefile       |   1 +
 lib/cpumask_test.c | 147 +++++++++++++++++++++++++++++++++++++++++++++

 3 files changed, 160 insertions(+)

 create mode 100644 lib/cpumask_test.c

lib/Kconfig.debug +0 -0

index 2e24db4bff19..e85e74646178 100644
@@ -2021,6 +2021,18 @@ config LKDTM

        Documentation on how to use the module can be found in Documentation/fault-injection/provoke-crashes.rst

+config CPUMASK_KUNIT_TEST
+       tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS +       depends on KUNIT
+       default KUNIT_ALL_TESTS
+       help
+         Enable to turn on cpumask tests, running at boot or module load time.
+
+         For more information on KUnit and unit tests in general, please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.

lib/Kconfig.debug +3 -0

+
+         If unsure, say N.
+

 config TEST_LIST_SORT
        tristate "Linked list sorting test" if !KUNIT_ALL_TESTS depends on KUNIT

lib/Makefile +0 -0

index bcc7e8ea0cde..9f9db1376538 100644
@@ -59,6 +59,7 @@ obj-$(CONFIG_TEST_BPF) += test_bpf.o

 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o obj-$(CONFIG_TEST_BITOPS) += test_bitops.o CFLAGS_test_bitops.o += -Werror +obj-$(CONFIG_CPUMASK_KUNIT_TEST) += cpumask_test.o obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o obj-$(CONFIG_TEST_SIPHASH) += test_siphash.o obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o

Quoted 8 lines

lib/cpumask_test.c

Quoted 5 lines

lib/cpumask_test.c new file +0 -0

new file mode 100644
index 000000000000..0f8059a5e93b

In order to make the tests at lib/ with more compliant naming, it would make more sense to name it test_cpumask.c.

That's what I had originally, exactly because I copied the naming from other files in lib/. That didn't match the style guide [1] which proposes the _test.c or _kunit.c suffix.

Most files in lib/ use the test_ prefix (45), but some use the _test.c suffix (4), or _kunit.c suffix (6). Of the "test_" ones, only 8 are actually KUnit test suites. I personally think the style guide makes a good argument to use a suffix, as that clearly places the test suite next to the relevant file in an alphabetic listing.

Based on the above, would you agree with using "cpumask_kunit.c" as the filename? That distinguishes it from the non-KUnit test files, and follows the style guide.

[1] https://docs.kernel.org/dev-tools/kunit/style.html#test-file-and-module-names

Quoted 4 lines

Thank you for the respin to the series! All tests are passing now.

Tested-by Maíra Canal <[email protected]>

Thank you for testing!

Best,
Sander

The maps to keep track of shared caches between CPUs on SMP systems are declared in asm/smp.h, among them specifically cpu_llc_shared_map. These maps are externally defined in cpu/smpboot.c. The latter is only compiled on CONFIG_SMP=y, which means the declared extern symbols from asm/smp.h do not have a corresponding definition on uniprocessor builds.

The inline cpu_llc_shared_mask() function from asm/smp.h refers to the map declaration mentioned above. This function is referenced in cacheinfo.c inside for_each_cpu() loop macros, to provide cpumask for the loop. On uniprocessor builds, the symbol for the cpu_llc_shared_map does not exist. However, the current implementation of for_each_cpu() also (wrongly) ignores the provided mask.

By sheer luck, the compiler thus optimises out this unused reference to cpu_llc_shared_map, and the linker therefore does not require the cpu_llc_shared_mask to actually exist on uniprocessor builds. Only on SMP bulids does smpboot.o exist to provide the required symbols.

To no longer rely on compiler optimisations for successful uniprocessor builds, move the definitions of cpu_llc_shared_map and cpu_l2c_shared_map from smpboot.c to cacheinfo.c.

Signed-off-by Sander Vanheule <[email protected]>

Cc Andy Shevchenko <[email protected]>

Cc Marco Elver <[email protected]>

Cc Greg Kroah-Hartman <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Valentin Schneider <[email protected]>

Cc Yury Norov <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Dave Hansen <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

---
Changes since v3:
- New patch

 arch/x86/kernel/cpu/cacheinfo.c | 6 ++++++
 arch/x86/kernel/smpboot.c       | 4 ----
 2 files changed, 6 insertions(+), 4 deletions(-)

Hi,

I am working on a UniProcessor system with latest linux-next kernel (20220803).
I observed two files "shared_cpu_map” and “shared_cpu_list” are missing for L3 cache (/sys/devices/system/cpu/cpu0/cache/index3). This causes lscpu version 2.34 to segfault. On further digging I figured below is the commit which introduced this problem.

https://lore.kernel.org/lkml/e78c55ecb98172356248a7a89da501479ead6ae0.1659077534.git.sander@svanheule.net/

I am not 100% certain what the proper fix for it is, but below changes fix this issue. I understand above patch is already confirmed for linux kernel 6.0, please suggest if we need fixing this in 6.0.

Regards,
Saurabh

lib/cpumask.c +0 -0

index b9728513a4d4..81fc2e35b5b1 100644

lib/cpumask.c +1 -0

         /* -1 is a legal arg here. */
         if (n != -1)
                 cpumask_check(n);
         return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
+#endif
  }
  EXPORT_SYMBOL(cpumask_next);

Hi Sander

lib/cpumask_test.c

Quoted 87 lines · Sander Vanheule

Add a basic suite of tests for cpumask, providing some tests for empty and completely filled cpumasks.

Signed-off-by Sander Vanheule <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

Suggested-by Yury Norov <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Dave Hansen <[email protected]>

Cc Greg Kroah-Hartman <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Marco Elver <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Valentin Schneider <[email protected]>

Cc Brendan Higgins <[email protected]>

Cc David Gow <[email protected]>

Cc Maíra Canal <[email protected]>

---
Changes since v4:
- Belated addition of Yury's Suggested-by:
- Follow KUnit style more closely
- Drop full check on cpu_possible_mask
- Update last check on cpu_possible_mask
- Log masks when starting test
- Update commit message

Changes since v3:
- Test for_each_cpu*() over empty mask and cpu_possible_mask
- Add Andy's Reviewed-by
- Use num_{online,present,possible}_cpus() for builtin masks
- Guard against CPU hotplugging during test for dynamic builtin CPU masks
Changes since v2:
- Rework for_each_* test macros, as suggested by Yury

Changes since v1:
- New patch

 lib/Kconfig.debug  |  12 ++++
 lib/Makefile       |   1 +
 lib/cpumask_test.c | 147 +++++++++++++++++++++++++++++++++++++++++++++

 3 files changed, 160 insertions(+)

 create mode 100644 lib/cpumask_test.c

lib/Kconfig.debug +0 -0

index 2e24db4bff19..e85e74646178 100644
@@ -2021,6 +2021,18 @@ config LKDTM

        Documentation on how to use the module can be found in Documentation/fault-injection/provoke-crashes.rst

+config CPUMASK_KUNIT_TEST
+       tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS +       depends on KUNIT
+       default KUNIT_ALL_TESTS
+       help
+         Enable to turn on cpumask tests, running at boot or module load time.
+
+         For more information on KUnit and unit tests in general, please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.

lib/Kconfig.debug +3 -0

+
+         If unsure, say N.
+

 config TEST_LIST_SORT
        tristate "Linked list sorting test" if !KUNIT_ALL_TESTS depends on KUNIT

lib/Makefile +0 -0

index bcc7e8ea0cde..9f9db1376538 100644
@@ -59,6 +59,7 @@ obj-$(CONFIG_TEST_BPF) += test_bpf.o

 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o obj-$(CONFIG_TEST_BITOPS) += test_bitops.o CFLAGS_test_bitops.o += -Werror +obj-$(CONFIG_CPUMASK_KUNIT_TEST) += cpumask_test.o obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o obj-$(CONFIG_TEST_SIPHASH) += test_siphash.o obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o

lib/cpumask_test.c new file +0 -0

new file mode 100644
index 000000000000..0f8059a5e93b

In order to make the tests at lib/ with more compliant naming, it would make more sense to name it test_cpumask.c.

Thank you for the respin to the series! All tests are passing now.

Tested-by Maíra Canal <[email protected]>