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 --- rust/syn/print.rs | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 rust/syn/print.rs (limited to 'rust/syn/print.rs') diff --git a/rust/syn/print.rs b/rust/syn/print.rs new file mode 100644 index 000000000..d73262cda --- /dev/null +++ b/rust/syn/print.rs @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +use proc_macro2::TokenStream; +use quote::ToTokens; + +pub(crate) struct TokensOrDefault<'a, T: 'a>(pub &'a Option); + +impl<'a, T> ToTokens for TokensOrDefault<'a, T> +where + T: ToTokens + Default, +{ + fn to_tokens(&self, tokens: &mut TokenStream) { + match self.0 { + Some(t) => t.to_tokens(tokens), + None => T::default().to_tokens(tokens), + } + } +} -- cgit v1.3.1