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/exports.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 rust/exports.c (limited to 'rust/exports.c') diff --git a/rust/exports.c b/rust/exports.c new file mode 100644 index 000000000..1b52460b0 --- /dev/null +++ b/rust/exports.c @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A hack to export Rust symbols for loadable modules without having to redo + * the entire `include/linux/export.h` logic in Rust. + * + * This requires Rust's new/future `v0` mangling scheme because the default one + * ("legacy") uses invalid characters for C identifiers (thus we cannot use the + * `EXPORT_SYMBOL_*` macros). + * + * All symbols are exported as GPL-only to guarantee no GPL-only feature is + * accidentally exposed. + */ + +#include + +#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym) + +#include "exports_core_generated.h" +#include "exports_bindings_generated.h" +#include "exports_kernel_generated.h" + +#ifndef CONFIG_RUST_INLINE_HELPERS +#include "exports_helpers_generated.h" +#endif + +// For modules using `rust/build_error.rs`. +#ifdef CONFIG_RUST_BUILD_ASSERT_ALLOW +EXPORT_SYMBOL_RUST_GPL(rust_build_error); +#endif -- cgit v1.3.1