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 --- lib/kunit/hooks-impl.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 lib/kunit/hooks-impl.h (limited to 'lib/kunit/hooks-impl.h') diff --git a/lib/kunit/hooks-impl.h b/lib/kunit/hooks-impl.h new file mode 100644 index 000000000..d8720f261 --- /dev/null +++ b/lib/kunit/hooks-impl.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Declarations for hook implementations. + * + * These will be set as the function pointers in struct kunit_hook_table, + * found in include/kunit/test-bug.h. + * + * Copyright (C) 2023, Google LLC. + * Author: David Gow + */ + +#ifndef _KUNIT_HOOKS_IMPL_H +#define _KUNIT_HOOKS_IMPL_H + +#include + +/* List of declarations. */ +void __printf(3, 4) __kunit_fail_current_test_impl(const char *file, + int line, + const char *fmt, ...); +void *__kunit_get_static_stub_address_impl(struct kunit *test, void *real_fn_addr); +bool __kunit_is_suppressed_warning_impl(bool count); + +/* Code to set all of the function pointers. */ +static inline void kunit_install_hooks(void) +{ + /* Install the KUnit hook functions. */ + kunit_hooks.fail_current_test = __kunit_fail_current_test_impl; + kunit_hooks.get_static_stub_address = __kunit_get_static_stub_address_impl; + kunit_hooks.is_suppressed_warning = __kunit_is_suppressed_warning_impl; +} + +#endif /* _KUNIT_HOOKS_IMPL_H */ -- cgit v1.3.1