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/objtool/weak.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 tools/objtool/weak.c (limited to 'tools/objtool/weak.c') diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c new file mode 100644 index 000000000..d6562f292 --- /dev/null +++ b/tools/objtool/weak.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2020 Matt Helsley + * Weak definitions necessary to compile objtool without + * some subcommands (e.g. check, orc). + */ + +#include +#include +#include +#include +#include + +#define UNSUPPORTED(name) \ +({ \ + fprintf(stderr, "error: objtool: " name " not implemented\n"); \ + return ENOSYS; \ +}) + +int __weak orc_dump(const char *_objname) +{ + UNSUPPORTED("ORC"); +} + +int __weak orc_create(struct objtool_file *file) +{ + UNSUPPORTED("ORC"); +} + +int __weak cmd_klp(int argc, const char **argv) +{ + UNSUPPORTED("klp"); +} -- cgit v1.3.1