From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/rv/kunit.h | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 include/rv/kunit.h (limited to 'include/rv/kunit.h') diff --git a/include/rv/kunit.h b/include/rv/kunit.h new file mode 100644 index 000000000..31e0b93c4 --- /dev/null +++ b/include/rv/kunit.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2026-2029 Red Hat, Inc. Gabriele Monaco + * + * Declaration of wrappers to allow mocking core functionality, like current, + * and other testing utilities. + * Necessary only when mocking may be needed. If the RV KUnit test is + * enabled, the wrappers incur an additional function call overhead. + */ + +#ifndef _RV_KUNIT_H +#define _RV_KUNIT_H + +#if IS_ENABLED(CONFIG_RV_MONITORS_KUNIT_TEST) + +#include +#include +#include + +int rv_set_testing(struct kunit_suite *suite); +void rv_clear_testing(struct kunit_suite *suite); + +#define RV_KUNIT_MAX_MOCK_TASKS 8 + +struct rv_kunit_ctx { + int reactions, expected; + int mock_task_count; + struct task_struct *mock_tasks[RV_KUNIT_MAX_MOCK_TASKS]; +}; + +#define RV_KUNIT_EXPECT_REACTION(test, ctx) \ + do { \ + KUNIT_EXPECT_EQ(test, ctx->reactions, ++ctx->expected); \ + if (ctx->reactions != ctx->expected) \ + ctx->expected = ctx->reactions; \ + } while (0) + +#define RV_KUNIT_EXPECT_NO_REACTION(test, ctx) \ + do { \ + KUNIT_EXPECT_EQ(test, ctx->reactions, ctx->expected); \ + if (ctx->reactions != ctx->expected) \ + ctx->expected = ctx->reactions; \ + } while (0) + +#define RV_KUNIT_EXPECT_REACTION_HERE(test, ctx) \ + for (int __done = ({ RV_KUNIT_EXPECT_NO_REACTION(test, ctx); 0; }); \ + !__done; \ + __done = ({ RV_KUNIT_EXPECT_REACTION(test, ctx); 1; })) + +struct rv_kunit_mon { + struct rv_monitor *rv_this; + int (*monitor_init)(void); + void (*monitor_destroy)(void); + bool is_per_task; + int *task_slot; + void (*task_reset)(struct task_struct *task); +}; + +void prepare_test(struct kunit *test, const struct rv_kunit_mon *mon); +void teardown_test(void *arg); +struct task_struct *rv_kunit_alloc_mock_task(struct kunit *test); + +void rv_mock_current(struct task_struct *tsk); +struct task_struct *rv_get_mock_current(void); + +#define rv_get_current() (unlikely(kunit_get_current_test()) ? rv_get_mock_current() : current) + +#else /* !CONFIG_RV_MONITORS_KUNIT_TEST */ + +#define rv_get_current() current + +#endif /* CONFIG_RV_MONITORS_KUNIT_TEST */ +#endif /* _RV_KUNIT_H */ -- cgit v1.3.1