bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/drivers/base/power/qos-test.c b/drivers/base/power/qos-test.c
new file mode 100644
index 000000000..79fc6c441
--- /dev/null
+++ b/drivers/base/power/qos-test.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+#include <kunit/test.h>
+#include <linux/pm_qos.h>
+
+/* Basic test for aggregating two "min" requests */
+static void freq_qos_test_min(struct kunit *test)
+{
+	struct freq_constraints	qos;
+	struct freq_qos_request	req1, req2;
+	int ret;
+
+	freq_constraints_init(&qos);
+	memset(&req1, 0, sizeof(req1));
+	memset(&req2, 0, sizeof(req2));
+
+	ret = freq_qos_add_request(&qos, &req1, FREQ_QOS_MIN, 1000);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	ret = freq_qos_add_request(&qos, &req2, FREQ_QOS_MIN, 2000);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN), 2000);
+
+	ret = freq_qos_remove_request(&req2);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN), 1000);
+
+	ret = freq_qos_remove_request(&req1);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN),
+			FREQ_QOS_MIN_DEFAULT_VALUE);
+}
+
+/* Test that requests for MAX_DEFAULT_VALUE have no effect */
+static void freq_qos_test_maxdef(struct kunit *test)
+{
+	struct freq_constraints	qos;
+	struct freq_qos_request	req1, req2;
+	int ret;
+
+	freq_constraints_init(&qos);
+	memset(&req1, 0, sizeof(req1));
+	memset(&req2, 0, sizeof(req2));
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MAX),
+			FREQ_QOS_MAX_DEFAULT_VALUE);
+
+	ret = freq_qos_add_request(&qos, &req1, FREQ_QOS_MAX,
+			FREQ_QOS_MAX_DEFAULT_VALUE);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	ret = freq_qos_add_request(&qos, &req2, FREQ_QOS_MAX,
+			FREQ_QOS_MAX_DEFAULT_VALUE);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	/* Add max 1000 */
+	ret = freq_qos_update_request(&req1, 1000);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MAX), 1000);
+
+	/* Add max 2000, no impact */
+	ret = freq_qos_update_request(&req2, 2000);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MAX), 1000);
+
+	/* Remove max 1000, new max 2000 */
+	ret = freq_qos_remove_request(&req1);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MAX), 2000);
+}
+
+/*
+ * Test that a freq_qos_request can be added again after removal
+ *
+ * This issue was solved by commit 05ff1ba412fd ("PM: QoS: Invalidate frequency
+ * QoS requests after removal")
+ */
+static void freq_qos_test_readd(struct kunit *test)
+{
+	struct freq_constraints	qos;
+	struct freq_qos_request	req;
+	int ret;
+
+	freq_constraints_init(&qos);
+	memset(&req, 0, sizeof(req));
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN),
+			FREQ_QOS_MIN_DEFAULT_VALUE);
+
+	/* Add */
+	ret = freq_qos_add_request(&qos, &req, FREQ_QOS_MIN, 1000);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN), 1000);
+
+	/* Remove */
+	ret = freq_qos_remove_request(&req);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN),
+			FREQ_QOS_MIN_DEFAULT_VALUE);
+
+	/* Add again */
+	ret = freq_qos_add_request(&qos, &req, FREQ_QOS_MIN, 2000);
+	KUNIT_EXPECT_EQ(test, ret, 1);
+	KUNIT_EXPECT_EQ(test, freq_qos_read_value(&qos, FREQ_QOS_MIN), 2000);
+}
+
+static struct kunit_case pm_qos_test_cases[] = {
+	KUNIT_CASE(freq_qos_test_min),
+	KUNIT_CASE(freq_qos_test_maxdef),
+	KUNIT_CASE(freq_qos_test_readd),
+	{},
+};
+
+static struct kunit_suite pm_qos_test_module = {
+	.name = "qos-kunit-test",
+	.test_cases = pm_qos_test_cases,
+};
+kunit_test_suites(&pm_qos_test_module);