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/tree-checker.h | 83 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 fs/btrfs/tree-checker.h (limited to 'fs/btrfs/tree-checker.h') diff --git a/fs/btrfs/tree-checker.h b/fs/btrfs/tree-checker.h new file mode 100644 index 000000000..833e2fd98 --- /dev/null +++ b/fs/btrfs/tree-checker.h @@ -0,0 +1,83 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) Qu Wenruo 2017. All rights reserved. + */ + +#ifndef BTRFS_TREE_CHECKER_H +#define BTRFS_TREE_CHECKER_H + +#include +#include + +struct extent_buffer; +struct btrfs_fs_info; +struct btrfs_chunk; +struct btrfs_key; + +/* All the extra info needed to verify the parentness of a tree block. */ +struct btrfs_tree_parent_check { + /* + * The owner check against the tree block. + * + * Can be 0 to skip the owner check. + */ + u64 owner_root; + + /* + * Expected transid, can be 0 to skip the check, but such skip + * should only be utilized for backref walk related code. + */ + u64 transid; + + /* + * The expected first key. + * + * This check can be skipped if @has_first_key is false, such skip + * can happen for case where we don't have the parent node key, + * e.g. reading the tree root, doing backref walk. + */ + struct btrfs_key first_key; + bool has_first_key; + + /* The expected level. Should always be set. */ + u8 level; +}; + +enum btrfs_tree_block_status { + BTRFS_TREE_BLOCK_CLEAN, + BTRFS_TREE_BLOCK_INVALID_NRITEMS, + BTRFS_TREE_BLOCK_INVALID_PARENT_KEY, + BTRFS_TREE_BLOCK_BAD_KEY_ORDER, + BTRFS_TREE_BLOCK_INVALID_LEVEL, + BTRFS_TREE_BLOCK_INVALID_FREE_SPACE, + BTRFS_TREE_BLOCK_INVALID_OFFSETS, + BTRFS_TREE_BLOCK_INVALID_BLOCKPTR, + BTRFS_TREE_BLOCK_INVALID_ITEM, + BTRFS_TREE_BLOCK_INVALID_OWNER, + BTRFS_TREE_BLOCK_WRITTEN_NOT_SET, +}; + + +#define BTRFS_BLOCK_GROUP_VALID (BTRFS_BLOCK_GROUP_TYPE_MASK | \ + BTRFS_BLOCK_GROUP_PROFILE_MASK | \ + BTRFS_BLOCK_GROUP_REMAPPED) + +/* + * Exported simply for btrfs-progs which wants to have the + * btrfs_tree_block_status return codes. + */ +enum btrfs_tree_block_status __btrfs_check_leaf(struct extent_buffer *leaf); +enum btrfs_tree_block_status __btrfs_check_node(struct extent_buffer *node); + +int btrfs_check_leaf(struct extent_buffer *leaf); +int btrfs_check_node(struct extent_buffer *node); + +int btrfs_check_chunk_valid(const struct btrfs_fs_info *fs_info, + const struct extent_buffer *leaf, + const struct btrfs_chunk *chunk, u64 logical, + u32 sectorsize); +int btrfs_check_eb_owner(const struct extent_buffer *eb, u64 root_owner); +int btrfs_verify_level_key(struct extent_buffer *eb, + const struct btrfs_tree_parent_check *check); + +#endif -- cgit v1.3.1