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/root-tree.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 fs/btrfs/root-tree.h (limited to 'fs/btrfs/root-tree.h') diff --git a/fs/btrfs/root-tree.h b/fs/btrfs/root-tree.h new file mode 100644 index 000000000..8f5739e73 --- /dev/null +++ b/fs/btrfs/root-tree.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_ROOT_TREE_H +#define BTRFS_ROOT_TREE_H + +#include + +struct fscrypt_str; +struct extent_buffer; +struct btrfs_key; +struct btrfs_root; +struct btrfs_root_item; +struct btrfs_path; +struct btrfs_fs_info; +struct btrfs_block_rsv; +struct btrfs_trans_handle; + +int btrfs_subvolume_reserve_metadata(struct btrfs_root *root, + struct btrfs_block_rsv *rsv, + int nitems, bool use_global_rsv); +int btrfs_add_root_ref(struct btrfs_trans_handle *trans, u64 root_id, + u64 ref_id, u64 dirid, u64 sequence, + const struct fscrypt_str *name); +int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id, + u64 ref_id, u64 dirid, u64 *sequence, + const struct fscrypt_str *name); +int btrfs_del_root(struct btrfs_trans_handle *trans, const struct btrfs_key *key); +int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, + const struct btrfs_key *key, + struct btrfs_root_item *item); +int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct btrfs_key *key, struct btrfs_root_item *item); +int btrfs_find_root(struct btrfs_root *root, const struct btrfs_key *search_key, + struct btrfs_path *path, struct btrfs_root_item *root_item, + struct btrfs_key *root_key); +int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info); +void btrfs_set_root_node(struct btrfs_root_item *item, + struct extent_buffer *node); +void btrfs_check_and_init_root_item(struct btrfs_root_item *item); +void btrfs_update_root_times(struct btrfs_trans_handle *trans, struct btrfs_root *root); + +#endif -- cgit v1.3.1