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/bio.h | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 fs/btrfs/bio.h (limited to 'fs/btrfs/bio.h') diff --git a/fs/btrfs/bio.h b/fs/btrfs/bio.h new file mode 100644 index 000000000..303ed6c71 --- /dev/null +++ b/fs/btrfs/bio.h @@ -0,0 +1,133 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * Copyright (C) 2022 Christoph Hellwig. + */ + +#ifndef BTRFS_BIO_H +#define BTRFS_BIO_H + +#include +#include +#include +#include "tree-checker.h" + +struct btrfs_bio; +struct btrfs_fs_info; +struct btrfs_inode; + +#define BTRFS_BIO_INLINE_CSUM_SIZE 64 + +typedef void (*btrfs_bio_end_io_t)(struct btrfs_bio *bbio); + +/* + * Highlevel btrfs I/O structure. It is allocated by btrfs_bio_alloc and + * passed to btrfs_submit_bbio() for mapping to the physical devices. + */ +struct btrfs_bio { + /* + * Inode and offset into it that this I/O operates on. + * + * If the inode is a data one, csum verification and read-repair + * will be done automatically. + * If the inode is a metadata one, everything is handled by the caller. + */ + struct btrfs_inode *inode; + u64 file_offset; + + union { + /* + * For data reads: checksumming and original I/O information. + * (for internal use in the btrfs_submit_bbio() machinery only) + */ + struct { + u8 *csum; + u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE]; + struct bvec_iter saved_iter; + }; + + /* + * For data writes: + * - ordered extent covering the bio + * - pointer to the checksums for this bio + * - original physical address from the allocator + * (for zone append only) + * - original logical address, used for checksumming fscrypt bios + */ + struct { + struct btrfs_ordered_extent *ordered; + struct btrfs_ordered_sum *sums; + struct work_struct csum_work; + struct completion csum_done; + struct bvec_iter csum_saved_iter; + u64 orig_physical; + u64 orig_logical; + }; + + /* For metadata reads: parentness verification. */ + struct btrfs_tree_parent_check parent_check; + }; + + /* For internal use in read end I/O handling */ + struct work_struct end_io_work; + + /* End I/O information supplied to btrfs_bio_alloc */ + btrfs_bio_end_io_t end_io; + void *private; + + atomic_t pending_ios; + u16 mirror_num; + + /* Save the first error status of split bio. */ + blk_status_t status; + + /* Use the commit root to look up csums (data read bio only). */ + bool csum_search_commit_root:1; + + /* + * Since scrub will reuse btree inode, we need this flag to distinguish + * scrub bios. + */ + bool is_scrub:1; + + /* Whether the bio is coming from copy_remapped_data_io(). */ + bool is_remap:1; + + /* Whether the csum generation for data write is async. */ + bool async_csum:1; + + /* Whether the bio is written using zone append. */ + bool can_use_append:1; + + /* + * This member must come last, bio_alloc_bioset will allocate enough + * bytes for entire btrfs_bio but relies on bio being last. + */ + struct bio bio; +}; + +static inline struct btrfs_bio *btrfs_bio(struct bio *bio) +{ + return container_of(bio, struct btrfs_bio, bio); +} + +int __init btrfs_bioset_init(void); +void __cold btrfs_bioset_exit(void); + +void btrfs_bio_init(struct btrfs_bio *bbio, struct btrfs_inode *inode, u64 file_offset, + btrfs_bio_end_io_t end_io, void *private); +struct btrfs_bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf, + struct btrfs_inode *inode, u64 file_offset, + btrfs_bio_end_io_t end_io, void *private); +void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status); + +/* Submit using blkcg_punt_bio_submit. */ +#define REQ_BTRFS_CGROUP_PUNT REQ_FS_PRIVATE + +void btrfs_submit_bbio(struct btrfs_bio *bbio, int mirror_num); +void btrfs_submit_repair_write(struct btrfs_bio *bbio, int mirror_num, bool dev_replace); +int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 fileoff, + u32 length, u64 logical, const phys_addr_t paddrs[], + unsigned int step, int mirror_num); + +#endif -- cgit v1.3.1