selftests/bpf: Check that JMP32 pointer vs zero jumps are not predictedgrafted

Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which
the verifier used to skip, contains an out of bounds map value access,
hence w/o the previous patch the program is accepted. See previous patch
for detailed description.

Reported-by: Nicholas Carlini <npc@anthropic.com>
Suggested-by: Nicholas Carlini <npc@anthropic.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 18 insertions, 0 deletions

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<T>);
+
+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),
+        }
+    }
+}