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 --- fs/btrfs/print-tree.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 fs/btrfs/print-tree.h (limited to 'fs/btrfs/print-tree.h') diff --git a/fs/btrfs/print-tree.h b/fs/btrfs/print-tree.h new file mode 100644 index 000000000..d0e620bf5 --- /dev/null +++ b/fs/btrfs/print-tree.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + */ + +#ifndef BTRFS_PRINT_TREE_H +#define BTRFS_PRINT_TREE_H + +#include + +/* Buffer size to contain tree name and possibly additional data (offset) */ +#define BTRFS_ROOT_NAME_BUF_LEN 48 + +struct extent_buffer; +struct btrfs_key; + +void btrfs_print_leaf(const struct extent_buffer *l); +void btrfs_print_tree(const struct extent_buffer *c, bool follow); +const char *btrfs_root_name(const struct btrfs_key *key, char *buf); + +#endif -- cgit v1.3.1