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/trace/events/notifier.h | 69 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 include/trace/events/notifier.h (limited to 'include/trace/events/notifier.h') diff --git a/include/trace/events/notifier.h b/include/trace/events/notifier.h new file mode 100644 index 000000000..26b298a31 --- /dev/null +++ b/include/trace/events/notifier.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM notifier + +#if !defined(_TRACE_NOTIFIERS_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_NOTIFIERS_H + +#include + +DECLARE_EVENT_CLASS(notifier_info, + + TP_PROTO(void *cb), + + TP_ARGS(cb), + + TP_STRUCT__entry( + __field(void *, cb) + ), + + TP_fast_assign( + __entry->cb = cb; + ), + + TP_printk("%ps", __entry->cb) +); + +/* + * notifier_register - called upon notifier callback registration + * + * @cb: callback pointer + * + */ +DEFINE_EVENT(notifier_info, notifier_register, + + TP_PROTO(void *cb), + + TP_ARGS(cb) +); + +/* + * notifier_unregister - called upon notifier callback unregistration + * + * @cb: callback pointer + * + */ +DEFINE_EVENT(notifier_info, notifier_unregister, + + TP_PROTO(void *cb), + + TP_ARGS(cb) +); + +/* + * notifier_run - called upon notifier callback execution + * + * @cb: callback pointer + * + */ +DEFINE_EVENT(notifier_info, notifier_run, + + TP_PROTO(void *cb), + + TP_ARGS(cb) +); + +#endif /* _TRACE_NOTIFIERS_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1