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/relocation.h | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 fs/btrfs/relocation.h (limited to 'fs/btrfs/relocation.h') diff --git a/fs/btrfs/relocation.h b/fs/btrfs/relocation.h new file mode 100644 index 000000000..bb7a86e7d --- /dev/null +++ b/fs/btrfs/relocation.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_RELOCATION_H +#define BTRFS_RELOCATION_H + +#include + +struct extent_buffer; +struct btrfs_fs_info; +struct btrfs_root; +struct btrfs_trans_handle; +struct btrfs_ordered_extent; +struct btrfs_pending_snapshot; + +static inline bool should_relocate_using_remap_tree(const struct btrfs_block_group *bg) +{ + if (!btrfs_fs_incompat(bg->fs_info, REMAP_TREE)) + return false; + + if (bg->flags & (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA_REMAP)) + return false; + + return true; +} + +int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start, + bool verbose); +int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, struct btrfs_root *root); +int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, + struct btrfs_root *root); +int btrfs_recover_relocation(struct btrfs_fs_info *fs_info); +int btrfs_reloc_clone_csums(struct btrfs_ordered_extent *ordered); +int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + const struct extent_buffer *buf, + struct extent_buffer *cow); +void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending, + u64 *bytes_to_reserve); +int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans, + struct btrfs_pending_snapshot *pending); +int btrfs_should_cancel_balance(const struct btrfs_fs_info *fs_info); +struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr); +bool btrfs_should_ignore_reloc_root(const struct btrfs_root *root); +u64 btrfs_get_reloc_bg_bytenr(struct btrfs_fs_info *fs_info); +int btrfs_translate_remap(struct btrfs_fs_info *fs_info, u64 *logical, u64 *length); +int btrfs_remove_extent_from_remap_tree(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + u64 bytenr, u64 num_bytes); +int btrfs_last_identity_remap_gone(struct btrfs_chunk_map *chunk_map, + struct btrfs_block_group *bg); + +#endif -- cgit v1.3.1