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 --- tools/lib/api/debug-internal.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 tools/lib/api/debug-internal.h (limited to 'tools/lib/api/debug-internal.h') diff --git a/tools/lib/api/debug-internal.h b/tools/lib/api/debug-internal.h new file mode 100644 index 000000000..5a5820c11 --- /dev/null +++ b/tools/lib/api/debug-internal.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __API_DEBUG_INTERNAL_H__ +#define __API_DEBUG_INTERNAL_H__ + +#include "debug.h" + +#define __pr(func, fmt, ...) \ +do { \ + if ((func)) \ + (func)("libapi: " fmt, ##__VA_ARGS__); \ +} while (0) + +extern libapi_print_fn_t __pr_warn; +extern libapi_print_fn_t __pr_info; +extern libapi_print_fn_t __pr_debug; + +#define pr_warn(fmt, ...) __pr(__pr_warn, fmt, ##__VA_ARGS__) +#define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__) +#define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__) + +#endif /* __API_DEBUG_INTERNAL_H__ */ -- cgit v1.3.1